A: Mike McArtor, copyeditor for DailyMTG:
A timely question, considering this past weekend's Pro Tour! (I certainly didn't plan it that way, I'm sure.) The good news is that the Grand Prix schedule for 2014 is already available. There are going to be forty-six of them! And what a great time to start attending GPs, as the prize payouts are also increasing next year!
If your eventual goal is to get on the Pro Tour, you might also want to consider attending a Pro Tour Qualifier in your area! We're currently neck deep into the Pro Tour Born of the Gods qualifier season, which features Theros Limited (Swiss rounds of Sealed with Draft for the Top 8). But if none of those are near you (it happens), despair not, for you can also compete in Magic Online PTQs.
Since you're looking at playing in GPs you probably already know this, but for the sake of completeness it's best that I also mention Friday Night Magic. They're a great place to get in some practice with whatever format your local store runs.
Lastly, you probably have heard that there are going to be four Pro Tours next year (in addition to Worlds Week), but this past weekend we revealed when and where they're going to happen.
I hope all that helps! :)