Defense is a key to basketball success. If you score, you may win, but if they don’t score, you can’t lose.
You always want your defense to be aggressive and hard, but clean so you stay out of foul trouble. Many defensive skills are taught in reaction to what the offense does, but a good defender can take the offense out of their comfort zone. (See these basketball defense drills.)
Several components can help you step up your defensive game.
The basic basketball stance consists of sitting low with your feet wide and knees bent, ready to move by staying balanced on the balls of your feet. The player who is lower and still able to move quickly has the advantage. The lower you keep your center of gravity, the more ready you are to jump, box out or get to the ball. Even 5’3″ Muggsy Bogues played low on defense to optimize his game. (Try this stance-improving exercise.)
Ideally, you want to sit about an arm’s length away from your opponent (more or less, depending on how quick he is). In this position, extend your arm to where the ball is. If he is dribbling with his left hand, extend your right arm out in front of the ball. Your free hand should be in the passing lane to cut off any easy passes.
Most players are taught to slide by stepping with their lead foot, pointing their toes where they are going and then sliding the back foot to catch up. Instead, keep your toes straight and push off your back foot to laterally jump to your lead foot. This is much more explosive and covers more space faster.
Don’t try and steal the ball from the player. Steal it off the floor to avoid a foul. Staying low and using the proper sliding technique will help you quickly swipe the ball away.