Harmony Between Your iPhone and Gmail, Google Cal, etc.

It seems like just about every single article says either Apple or Google has a great product for one reason or another. I emphasize the "or" because the topic seems to be getting as polarized as politics. I can't imagine my daily life without the stunning simplicity, convenience, and technological bliss that is the marriage of Apple and Google products. I wanted to put together this guide to help out friends, family, and anyone else who wants the same.

I know the post is long, but this is as exhaustive of a summary and guide as I've seen on the internet. I hope it helps to better your experience of iOS and Google products working in a wonderful harmony!

My Devices & Services

• iPhone 4S & iPad 2 (same setup for both is recommended)
• Gmail
• Google Calendar
• All contacts are in Gmail

Setup

Account Types on the iPhone

This isn't as simple as adding a Gmail type account to your iOS device, this is the primary reason that most people aren't enjoying this setup.

Add a new Exchange account by selecting Settings (app) > Mail, Contacts, Calendars > Add Account...

Fill out your Email, Password, and add any description you like (mine is just "Gmail").

Press Next, there will be more to fill out. Note that your email address is your username @ your domain, so you should either leave the "Domain" blank and have your full email address as your username, or do what I do below. It shouldn't technically matter which way you chose.

Press Done.

Settings

Here are the rest of my settings for the account:

• Sync Mail, Contacts, Calendars, and Reminders. 
• Mail - This is a true sync (using the IMAP protocol), so if you delete on your iPhone you Archive it in Gmail. The exact contents of the Inbox on your phone will represent the Inbox on the server. This gets rid of the old-school concept of downloading a message off the server where the message is literally removed from the server (this technology was known as POP3). The question I get most often is how to actually delete an email - you must select Move To... then the Trash folder, just as you would move it to any other folder.
• Please note: You will need to enable IMAP access in your Gmail Settings, last I checked this is disabled be default. It is simple to do, please follow this guide.
• Contacts - Gmail keeps the golden master copy of my contacts list. I keep nothing local on the phone. This makes my life a breeze when I jump back to Gmail.com. I can also easily edit large groups of contacts on the web. iCloud has similar offerings, I just prefer Gmail so it'd be silly not to have my contacts in the same place. P.S. I suggest populating the contact's birthday, this way it'll show up on your calendar!
• Calendars - Calendars run my life. Anything I am doing or my wife is doing had better be in the calendar or I likely won't show up. I do as much event management on my phone as on the computer, it's nice to have it instantly sync both ways.
• Reminders - I'm a bit weird here. I LOVE reminders and use them constantly. I don't like Gmail's implementation of reminders (it isn't as nice of a user interface or as functionally laid out as iCloud), so even though I sync them, I actually strictly use iCloud for my reminders. 99% of the time I use my iPhone to manage Reminders, but on my work PC I also use iCloud.com. Of course the iPad has the same native app that the iPhone has, and Macs running OS X 10.8 or later (Mountain Lion) have the same Reminders app there as well.
• Oddly enough, you can create a new shared reminders list from the iCloud.com app or the Mac's native app, but you cannot create a new shared reminders list from an iOS device. You can edit and manage items on those shared lists though, so at most this is the slightest of "inconveniences" if you can even call it that.

Mail

• Mail Days to Sync - This is a tricky one for some. I suggest you personally subscribe to the "Inbox Zero" lifestyle where you don't keep email in your inbox. Tools like Gmail's labels and plugins like Boomerang just make it too easy and there's no reason to keep email around in the inbox. This doesn't mean getting rid of email, on the contrary I keep every single email that isn't junk or a daily mailer from LivingSocial or Groupon type sites. If you keep a relatively empty inbox I suggest syncing all mail in your Inbox. Consider a change in practice if you've never archived anything or have thousands of emails in your inbox.
• Mail Folders to Push - This setting selects which folders (Inbox is technically a folder) will by synced to the server. This means every email in that folder on the server will also be on your phone. I recommend only Inbox (default) for 99% of folks out there. However, some of you have advanced setups where you've got secondary accounts set up that automatically get labeled and archived (neat Gmail magic, if you don't know what I mean I've done a blog post that talks about it). For those power users you might want to push your other "Inboxes" as well.
• Keep in mind that even if you only check Inbox you can still see the entire folder hierarchy structure you have in place. You can also go into those folders and download their contents to view or manage emails. The difference is that those folders won't be actively synced and if you open them that will initiate a download of that folder's contents from the server at that time.

Note: These settings apply only to this particular account.

Note: The rest of the settings I'll cover apply to all accounts, not just your newly setup Gmail account. There are exceptions like Push/Pull, you can have a different account not setup for Pull. If you want additional details just ask in the comments and I'll get back to you usually within a few hours.

• Fetch New Data - Push. Push. Push. Enough said. If you want pull, set it up as a Gmail type account, I don't see any reason to do this for your iPhone. The "Gmail" account type for iOS doesn't support Push, this is why I suggest setting it up as an Exchange account. With that being said, what is Push and what is "Pull"?
• Push - Any folder you selected for "Mail Folders to Push" above will have emails "pushed" to your phone instantly when that email is received. Often I'll even see it come through on my phone a second or two before I see it in my inbox on gmail.com.
• Benefits (no cons if you ask me):
1. Emails show up instantly.
2. Your phone only gets email when there is new email to be grabbed. This saves battery life and network traffic.
• Pull - Every X minutes (this amount of time is adjustable) your phone will go and check the server for any new email (or changes to folder contents of any kind) for every folder you selected for "Mail Folders to Push" in the previous step. 
• Cons (no benefits if you ask me):
1. There is a delay between when you get an email and when your phone gets an email. This delay is the time between receiving the email and the next time your phone goes to check for emails. On the iPhone the minimum "Pull" time is 15 minutes, the maximum is just any time you open your Mail app. This means that new emails won't ever be delivered to your phone until you open the Mail app - I cannot imagine why someone would do this.
2. This uses more network traffic because whether or not you have a new email it has to go and check the server for emails.
3. This decreases battery life because it checks the server every X minutes 24/7.
• Show - This determines how many emails will be shown in a synced folder (i.e. Inbox). I show 200 emails (default) since I never get anywhere near that number in my Inbox anyway. If you've got a full inbox and see performance issues, consider lowering this. I have no idea if you'd ever see performance issues though. The max is 1,000. You can show more by tapping "Show More..." if you've hit this limit but the folder contains more items.
• Show To/CC Label - This will show or hide the To/CC icon that will appear on a message in a folder to indicate whether you are on the To or the CC of an email. It requires very little real estate on the screen and can be very handy if you're often on larger email threads (mostly a work account thing for me, but this setting applies to all email accounts on the phone).
• Ask Before Deleting - When you tap the trash icon, this will confirm by asking you if you're sure you want to delete the message. As we discussed, for an Exchange Gmail account (what we just setup) this actually means archive and not delete. I'm anal about handling and filing away email. Since deleting is just archiving, so this is total overkill, but I do it anyway.
• Load Remote Images - This option enables/disables emails downloading remote images from the server. Many coupon emails or emails from websites use HTML which is a simplified website right there in your email. Rather than attaching all those images, they host them on a remote server so that the email they send you is much smaller. Personally, I want my email to look as good and natural as possible. I am not worried about data quotas or anything, so I have this on. If you're traveling abroad or near your data quota for the month consider disabling it.
• Organize By Thread - This option allows your phone to group emails from a conversation together. It greatly cleans up your folders and is much more visually appealing. Enable this. Right now, I'll wait. You may as well use carrier pigeons if you disable this option. Ok, maybe I'm exaggerating to entertain myself; please let me know if and why you don't use this in the comments.

• Always BCC Myself - If enabled, this will BCC you on every email you send from your device. I do this for work where we don't use gmail and sent messages don't appear in line with other messages like Gmail shows. Most people shouldn't do this.
• Increase Quote Level - This will increase the quote level a forwarded email; you've seen all the bars on the left side of an email that's been forwarded 25 times? Yeah, that. If you forward a lot of emails, don't do this because it is really annoying to the rest of us. 'On' is default and I've just never changed it. I'm not a frequent forwarder.
• Signature - This is your email signature that will appear at the bottom of emails you compose. New in iOS 6 you can have multiple signatures, unique to an email account! Note that by default this will have "-Sent from my iPhone" (or iPad or iPod Touch) when you first get the device. This being the default signature is why you see it so often, it isn't people being smug, they just haven't changed it.
• Default Account - Select what default account you want for sending a new email. When you have work & personal email, be careful here. When replying to an email, it'll reply with whatever the original was sent to, so this only applies to new emails.

Contacts

• Sort Order - This is the order that the contacts are sorted in your phone, not the way the names are viewed/displayed. "Last, First" makes the most sense to me, but I have every contact in there with a full name. If you have contacts like "Mom" and "Dad" (yes, my parents and my wife are all in there with their full names, yes I have taken "heat" for that) you might want to change this.
• Display Order - This is the way contacts are displayed on your phone. "First,Last" is more natural, but may be counterintuitive since you may not sort that way.
• My Info - I highly recommend everyone has themselves in their contact book with every piece of information you're willing to share, there are some good reasons.
• Siri - Siri uses this to route you home or to work and to remember connections like who your spouse/parents/siblings is/are.
• Bump/Contact Sharing - When you meet someone new you can use Bump or a similar "business card" sharing app to send someone your info. When you control the info in the business card it is up to you to have your contact represented professionally in their phone. Maybe it is just me, but I have a great appreciation for a well organized, nicely filled out contact card with a high resolution contact photo in my phone.
• Default Account - This is the account where any new contact you create will go unless you specify otherwise. Like I said, I keep all my personal contacts in Gmail, so naturally that's my default.
• There has been confusion on how to create a contact in a certain group. To do this you need to go into your Address Book, then into the group you want to add a contact in, then press the + to add them. If you create them in the "All Contacts" area of the Address Book, they will be added to your default account.
• Import SIM Contacts - Essentially this will import contacts from your SIM card to your local contacts on your iPhone (only AT&T and T-Mobile have those in the US for 3G and earlier networks, LTE uses a SIM card now too). Older phones used to store contacts here so they could be brought with you as you went to a new phone. When you import them here, they'll be added to your iPhone local contacts, not to your default account - I am pretty sure (not 100%). I haven't had to deal with this, if you need help here please ask in the comments and I can do some poking around to see how to solve problems that you might have with it.

Calendars

• New Invitation Alerts - PAY ATTENTION TO THIS ONE! This is a hidden gem if you ask me. By default this is on, I dislike that. What this does is play the alert tone that otherwise plays to alert you of a calendar event that's about to start, but it plays when a person sends you an invite regardless of when the event is for. I don't want an alert at midnight when someone sends me a lunch invitation for a month from now. I don't like this being enabled by default, particularly because I work with folks overseas who send invites in the middle of my night quite frequently.
• Time Zone Support - This one is tricky, in general it is best to have it turned on and to be aware of how it works, but use this information to determine what is best for you.
• This will make sure calendar invitations are handled properly when you send them to or get them from a time zone other than your own. If you do this often, I suggest enabling it.
• If this is enabled, and if you're planning an event in a different time zone and have an event at 2PM in that time zone then you will need to add it to your calendar for whatever time that is in the time zone you're currently in. This can be counterintuitive at first, but ultimately makes sense. If this is something you do often and your calendar is primarily just for your events (not for meetings with others), then you might want to consider disabling this. Unfortunately you cannot have 1 setting for 1 account (i.e. Work) and a different setting for another account (i.e. Personal).
• Sync - This option selects how long into the past to sync changes to an event. It doesn't clear events from your calendar that are older than this amount of time, but if you change something older than this, the change will not be synced to the server (Google Calendar). Similarly if you change an event on the Google Calendar website it won't sync the change to your phone. I've found 1 month back is more than sufficient, I see no reason to change the default here.
• Default Calendar - Make sure you've got this set how you want it if you have work and personal stuff on here. You don't want to send your boss a meeting invite from your Gmail account! Every time you create an event you can choose which calendar to put it on, this option just determine what the default is. I suggest making it whichever calendar you schedule more appointments on from your phone.
• Siri - As far as I have noticed Siri will only schedule on your default calendar, but  I haven't tried making Siri schedule work meetings for me so that might not be accurate.
• Shared Calendar Alerts - If enabled, this will alert you when there is a change to a calendar event on a shared calendar. If you share a calendar with a spouse this could be handy to know if something like your evening plans are how an hour earlier and you need to leave work early. Similar to New Invitation Alerts though, this could be annoying if you share a calendar with someone who is in a different time zone or is making changes while you sleep (and you don't use the new iOS 6 feature Do Not Disturb, which I suggest you do).

Alright, that epic novel sums up just about every detail of making my favorite email service (Gmail) play nicely with one of the world's most popular brands of phones (iPhones, and any iOS device really). Thank you to Heather (my sister) for the suggested topic of this post. I wish I would have kept track of the frequency of her tech help request iMessages before this was posted so that I can compare to them afterward :).

I know this is a long post, but there are a lot of people out there who use Gmail on an iPhone and are putting up with nuances that they don't realize they have full control over. Please share this with those people, it really is true that you can find harmony with both Google and Apple products together!