When I am missing more pitches than normal, EVERY TIME it is 2 things:

1 - Not tracking the ball all the way to the glove.

2 - Calling the pitch too soon.

These two things work in tandem too.

WATCH THE BALL ALL THE WAY TO THE GLOVE!!! If you do, #2 should not be an issue.

Another thing which has everything to do with that matter between your ears: PICK A ZONE AND STAY WITH IT!!! If you KNOW the zone you are going to call, relax, watch the ball to the glove, determine if it was presented well and in the zone you are going to call, make the call. While this sounds simple enough, every guy I talk to about missing pitches who is tracking the ball properly and have good timing is usually over-thinking their strike zone. Forget about the score, the play situation, coach complaints, etc...and call YOUR ZONE. If you are consistent, there should be no complaints beyond the 2nd inning.