When fielding fly balls, catching from a “camped” position is always best way. What I mean by “camped” is that you are lined up with the flight of the ball so that when it comes down, you are there waiting for it. When you can get to a camped position, you should make every effort to do that. That may mean sprinting to get there in time. If you have time and elect to just drift over and make a lazy backhand or forehand catch, there is greater chance of dropping the ball.
Team USA coach Mike Candrea and Amanda Freed give some tips
When the ball is hit over your head, back peddling is not a good way to get to the ball. Instead, from your starting position, you should determine if the ball is going over your left or right shoulder. You can make this determination quickly if you are focusing on the ball as it comes off the bat. Use a drop step to turn your body and run to the ball. If the ball is going over your right shoulder, you will drop step with the right foot. That way your body turns the right way so that you can keep your eyes on the ball. If you have time to sprint back and get into a camped position, do that. If not, you will have to attempt and over the shoulder catch. It isn’t as hard as it sounds. One of the drills I like to use is playing catch with a football and have the girls make a catch going deep. This also helps them to realize just how far they can run and still make a catch. This is how a short stop or 2nd base player can catch a pop fly way over by the foul lines.
Jessica Mendoza talks about going back on a fly ball.
Sliding CatchWhen a player is sprinting after the ball, they may find themselves approaching a fence or the ball may be lower than expected. Using a sliding motion, as if they were sliding into a base can quickly lower them to the level of the ball. Sliding close to the fence could help to avoid a collision with that fence. Always keep the thrust leg flexed to absorb any impact and avoid injury.