Do not flop...(unless you are great at it)

Trying to take a false charge will give you a bad reputation with the referees. If you get caught you wont be a refs favorite. Only flop when it looks natural...cheap but that is sometimes what the game is about. Think of the San Antonio Spurs for example, I haven't seen them play a fair game in my life yet they still win.

Force the dribbler to make the first move

Your the defender and the ball handler is just toying with your head, waiting for you to go for the steal while he dribbles back and forth and back and forth right in front of your face(I do this a lot). Your first reaction is to play in to his trick and go for that quick steal while he goes around you for an easy layup. Do not let this happen to you, while he continuously dribbles just move your eyes where ever the ball goes(or at least make it look like your awake), the ball handler will get bored and ultimately try to make a move. That is what you want him to do. If you make the first move he can anticipate it and go right around you. If he makes the first move, you can anticipate where he is going with the ball and the result will probably be a missed shot, a steal, or a block. All the good NBA defenders use this technique. In fact I was actually taught this method by a former NBA player!