Basketball is a fantastic games and the skill of the players is the main factor between a good and a bad player. Of course the height of the person may help, specially to catch the high pass and to catch the rebound but even the smaller player can have a serious impact on the game just think about Steve Nash, the great canadian start and you will agree with me that everything is possible if you improve your overall skill and your speed.
The following is a veru good drill you can use to improve your defense game or as a basketball coach the defense of your team. No need for fancy basketball equipment
or training aid equipment just basket balls
Group of Players form a circle around a single defender. Players in the circle must make passes to others in the circle, but may not pass to a player straight next to them. The sole defender must pressure the player with the ball and attempt to intercept or touch the ball. On an interception or a pass cut the passer replaces the defender in the middle and the exercise go on like that.
You can also add some variations and difficulty as the players get use to that drill. For example you can use two or more balls or you can use two or more defenders in the middle. Other way to make some change, you can modify the size of the circle for shorter or longer passes attempt. If you want to make sure every player find himself in the middle, you can put a time limit for each player as a defender or a time limit on ball handler to get off pass like 3-4-5 seconds. In that case the coach can use a whistle and a stopwatch togive the cue.
It is good for the defender but also for the offense, improve the fake pass before making the real pass. Improve your defense with high pressure on the ball holder, learn to get very active hands when you play and avoid the too cute pass or over the head of the defender, the kind of play that leads too often on turn over during the game.