Last season, one of the most mind-numbingly annoying situations the Spurs found themselves in time after time was their struggle to surpass their opposition in field goal attempts. Their opponents took more shots than they did in just about every single game, and it wasn't by a small margin. One or two shots aren't that difficult to overcome, but five to ten more shots are.
A defensive possession isn't over until you secure the rebound. San Antonio must be better at doing that and not allowing second-chance opportunities to the other team. They can't turn the ball over at a high rate.