Only try this on a low jump and with an adult/other person present but once your horse is set up and centered for the line close your eyes over the jump. It forces your brain to think about your movements to balance and move with the horse. I usually have my students close their eyes two strides before the jump when trying this exercise
Practice from the bottom up is what has majorly improved my eq. It builds the confidence and muscle memory when you really need it!!
I find what works for me is approaching the jump just keep thinking it every stride say to yourself eh hands forward that will tell your brain to contribute to helping your eq
Our brain can be tricky, placing us in one of 3 modes when it thinks we’re in danger (wether or not we really are): flight, fight, or freeze. I’ve experienced the freeze even during competition 😬 the best way out of it to me is bringing yourself back into the present moment such as feeling what your horse is doing, recognizing each step as it happens instead of wandering out to possible outcomes. I also sometimes try to “trick” myself into thinking things like I’m only doing cavalletis to keep my body relaxed. Doing so, keeps the mind in a calm state, letting you be able to focus on things like position even over a jump
Focus on one thing each session! I focus on my lower leg for a few sessions then once I feel that I’m happy with it then I’ll focus on something else like release, it all comes together slowly :)