This guy has some good tips on the proper technique to use when fielding a fly ball. Catching a baseball hit on the fly to the out-field is not hard but it does take many hours of practice. Practice catching fly baseballs will teach you how to judge the flight of the baseball, what angle you need to use when moving forward or backward, how to hold your glove and just how fast you are going to need to move to close with the ball. All this only comes through hours of practice until it comes naturally. You won't even need to think about what to do as you gain experience. You'll know as soon as the baseball comes off the hitter's bat how to react to put yourself in a position the catch the fly ball. Your baseball hat is important also as the bill on the hat will shade your eyes from the sun, allowing you to keep the ball in sight.
