Although you should continue to practice your jumpshot, there are plenty of other options as well. Once made consistent, floaters are one of the most effective ways to finish near a big man. If the defender is about five to ten feet out from the basket, a Euro-step (or two-step) is a very good move. Another thing you can do is take it all the way to the big man and try to go to the free throw line. Make sure that when you do this that the defender's feet are not set and that you protect the ball with your body and make contact with him, this could work almost every time. Good luck!