A lot of people recommend the 4x4 grid method where you draw a grid and follow the holes on paper instead of trying to keep it all in your head. Are you using that?
What I do is I start by marking the holes punched on the last frame. Then I compare that frame to the frame before it to see where the fold (line of reflection) was made. Then I reflect the holes on my grid, and repeat. It becomes pretty mechanical and you can do it and get 100% reliably that way. The only caveat is that if you do the reflection and get holes that exist where there is no paper in that frame, cross them out. Vague directions, I know, but maybe someone who gets what I'm trying to say can elaborate for me. I'll try to post an example if I can later.
