You should always follow these few defensive tips and you will prevent a lot of baskets.
1. Always know where the ball is so that you can help out team mates and read passes.
2. Never cross your legs, always slide when going sideways.
3. Always make sure you are between your man and the basket, if not then he just scored. Don’t be afraid to box him out or put your body on him to do this, Just don’t foul him.
4. Know if he is right handed or left handed. Maybe he can’t drive on his left. Find out so you can predict what his next move will be.
5. Always keep your hands up. Never at your sides. You can steal the ball, and block passes and shots if your hands are in the action.
6. Never slack off or else the offense will make you pay.
7. Watch the hips not the ball. Half of the reason why all of those And1 tricks work is because the defender goes for the opponents ball fakes. Just watch the hips and you wont bite on crossovers and pump fakes.
8. If the steal is there, go for it. If you don’t get it though make sure he isn’t going to get by you. Being aggressive makes the opponent afraid to dribble the ball near you.