For smaller jumps (below a meter) make sure you're just bending at the hips, not getting out of the saddle. I used to do that a lot, and I looked so wierd because I would like jump outta the saddle for these small jumps. Lol
My trainer made me do all of my jumping lessons in a bare back pad. It has really helped with strengthening my muscles and improving my balance. My position has really improved so I do highly suggest it!
To have a good jumping position, you need to first lower your heels. Don't compress your knees on the saddle! Your hips have to be right above your feet.
Keep your look ahead and don't fall forward.
The first times you can hold on to the mane to keep a better balance.
My advice would be to train a lot on small jumps and will see that your position will progress every time!
Good luck :)