Definitely weaken your grip-this will allow more wrist hinge also but in addition you need to try pausing at the top, slowing the transition, this gives you time to get your lower body moving ahead on the downswing. The quick transition will cause pull hooks or nasty duckies.
If you are flipping, slowing the downswing transition also helps with that too.
In any case, most problems are grounded in trying to rush the downswing in an effort to hit the ball further. Slower swing equals more center hits and better timing which equals great shots.
Good luck