He has to take better shots. Fran made a pretty good point during multiple broadcasts that he doesn't take a lot of high quality shots. A lot of his attempts are off-balance, not open, step-backs, etc. He isn't good enough for that. He shot better at WSU because he was a spot-up shooter.
If he takes higher quality shots, he will make a better percentage. If he turns into a jack machine, he will shoot a poor percentage.