Position wise it's going back to basics and think logically about biomechanics so where the weight naturally goes vs where you want it to go. So sitting tall with all your weight going down through all of your leg and into your heel as much as possible really helps sit your horse up, keep balanced and keeps them moving forward to the fence. Having tidy hands, tidy legs and using your core also helps your horse keep straight so minimise wiggling and possibly completely deter them from running out. Especially in jumping, always look for your next jump! You'll find your line and stride so much easier and if your horse is focused on you they won't be surprised at a jump even if it's a tight corner. While in your jumping position, keep your weight down through your leg and nice and close to the girth. Don't stress about folding right against your horse's neck; it's more effort for you and most likely will put extra weight over your horse's shoulder and might cause a rail. So keeping a supple hip to go with the movement and allow you to give enough will be more than enough. Release wise, do what ever you feel comfortable, whether direct or a crest. In show jumping it really doesn't matter at all. But to sum it up, sit tall, eyes always on your next jump (even when taking off and going over a jump), weight through all your leg (not just your heel) and above all have fun!!!