Many have talked about this team's collective basketball IQ and instincts. There are a lot of 'watchers' on this team and waiting for the ball to carom off the rim to go get it is not a recipe for success. Good rebounders start making an effort as the shooter is releasing the ball. Understand the angle the shot is coming from and look for some open space. Most of the work needs to be done before the ball hits the rim.
Diarra may be the player on the team with the best rebounding instincts, but you don't want your PG crashing the offensive boards if it is going to lead to some fast break the other way. Some guys can also just read the ball off a shooter's hands and pretty quickly know it's going to be short, long, left or right. AJ was really good at this. I think it was lost because he could also use his freakish jumping ability to get some rebounds sometimes, but he also had really good instincts. Last year, Cam and Newton were good rebounders for their position as well and you had Clingan who just ate up so much space and demanded so much attention underneath.
Finally, you also have to box out the shooter once he lands. There have been numerous times this year when the shooter has shot, and not have a body put on him, and they are free to get a rebound.