Originally Posted by hrsrdr
Ride a ton without stirrups, including eventually 2-point (jumping position) and over small jumps, and also tie your reins in a knot and go through a jumping grid with your hands out to the sides in "airplane position".
Just want to add to this part; jumping without reins is great, but be SUPER careful how you put your hands and arms. Don't fling them out to the sides, because you might spook your horse, and that's the last thing you want. My trainer always had me just move my hands about a foot away from the horse. You get the same out of it, but you're less likely to scare your horse while he/she is jumping. I've had a bad experience doing that and trust me, it was not pleasant. :)