When I was a kid, during the wood bat era, you could hear the sound from the batted ball. To some extent you can tell today even with the aluminum sound. It is certainly not as good as seeing the ball off the bat, but put your head down during practice and see if you can hear the direction of the ball. My children (4) did this as a routine. 1 couldn't see at night, the sound of the bat helped him with that 1st step. All of my 3 sons started in the outfield in HS for 3 years and the single most important factor was not moving the wrong direction with the first step. My lone daughter played the outfield in college for 4 years also. Just remember no reaction is better than a negative reaction. Practice what you see and hear!