If you're a heavy user of Google services, it can be a little confusing to set up your Gmail, Google Calendar, and Google Contacts to sync with iOS. You can get all your Google services syncing (complete with push sync—that is, messages push to your phone as soon as you receive them) with iOS by setting up just one account. The trick is to choose Microsoft Exchange at the prompt instead of Gmail. This will give you access not only to your Gmail, but your calendars and contacts, and they will all sync directly to your phone—when you add a contact in Gmail or edit an event on Google Calendar, you'll see it show up on your phone without having to sync anything.