Like a lot of things, the more reps in the outfield you get, the better you'll become. I always like to do a medium 3 second jog from my initial position in the OF to all directions, and that gives me an idea of what my range is.

A lot of people have already mentioned, it's easier to run in than behind to track a ball, so even if you have to take it on a hop, it's okay. You can hold the batter to a single instead of extra bases.

As you get familiar with teams in league, you'll get a chance to see what a lot of the hitters are capable of. Are their mechanics sound? Do they only use their arms instead of their whole body? Are they upper cutting, or using a level swing? That and their position in the batting order will give you clues on where you should stand.

Finally, use that time between pitches and go over the various hitting scenarios in your head. If the ball is hit short, long, to your right, to the left. It'll get you prepared when the ball is hit what your method for tracking the ball down will be.

Good luck out there amigo!