Defense is all about desire. You can’t be afraid to work hard and get sandy. You also need to make sure that you are disciplined, have good footwork and can anticipate what the hitter is going to do. That is much easier said than done.
This video is a basic defensive drill to help develop good footwork habits and muscle memory. You can increase the level of difficulty as the athlete progresses through the drill. Eventually, you can add in the approach and hit to finish the play.