I just finished the Story Mode last night. Here are some tips I can share for some common issues:
For the "No Checks 1 v 1", for every
possession, I would start at the top of the key, even after I dunked it and got the ball back. Here's why: if you put the ball right back into the basket after a score, there's a chance that your opponent will steal the rebound. By dunking, getting the rebound, going all the way back to the top of the key, you can easily run by your opponent, dunk it, and he's nowhere close and no danger to steal the rebound. It's a slow, but safe way to ensure you keep scoring and keep the ball away from your opponent.
For those having trouble with the Superstar dunk, I followed the advice from this thread. When you get your 3 star ranking, walk over to the "Shut'em down" circle at the top of the key, stop, hold LT + RT, then hit X. Don't make the mistake that I, as well as others, did. Yes, in the real world, you would want a running start if you were to dunk. But, this is NBA Ballers where you can dunk the ball even while standing still! Many times, I would end up shooting the Super Shot, and not the dunk, which is probably the most frustrating experience ever.
To build up to 3 stars, often times I would Act-a-fool once, run back in front of the guy guarding me, then do it again, then go dunk it. It all depended on the shot clock. Getting from 0 stars to 2 stars is easy, but 2 stars to 3 can take forever if you only do one Act-a-fool at a time.