Start with your hands up by your head/ear. This should help
I have heard the exact opposite. Start with your hands lower.
What I find I do when I pop up is:
- I start my swing too early.
- Bring the bat up.
- Over stride my step.
- Drop the bat head down through the zone.
What I started doing:
- Waiting for the ball to get to me.
- Start with hands lower.
- Step is more compact.
- Force the bat head to be up.
I started with a tee, swing trainer stick that I made and whiffle golf balls. Started with slow motion swings and I felt a lot of unnatural movement. Then I began to try and eliminate those unnatural movements 1 by 1. I started picking up the tempo of my swing and I started to make better contact.
Then, I switched to softball bat, softball on tee, did the same as above. After I got the hang of that, I went to bp and real pitching.