Hi - I agree with the others. However I think there are some useful things that you can do, which don't need us to see your position (which incidentally would be good if you had shorteer stirrup lengths!)
Things to help you build up to jumping are:
- Cavelletti and pole work. Does your horse adjust his stride, is he careful over poles etc. It'll also help build up his balance and agility.
- Is you canter rhythmical and 'organised'. (i.e. is it at a steady tempo even when complting corners...)
- Can you maintain two point in walk/trot/canter, without using the neck for balance?
- Do you know the length of your horses stride (you can canter down one length of the school, then stride it out yourself so yu start to understand how much ground each stride covers...
There's some basic things to start with. You'll probably be doing them already if you're starting to jump soon. Best of luck and have fun!