There are some times I feel like I think too much in the box. I used to be much worse.
Two solutions I have found that seem to have worked for me:
Chew Gum (Blue Collar Baseball mentioned this)
Think the words "see the ball" (I got that one from a baseball mental book not sure what it was called)
Your first job as a hitter is to see the ball. Nothing can happen without that, and after that, everthing that happens is pretty much autopilot anyway.