This trick helped a lot with my horse: you place two poles in an inverted V shape on top of the top rail of the jump, so one end of each of these poles is lying on the rail close to the middle and the other end is on the ground further apart ( hard to explain without an image...). When you approach the jump it kind of looks like a funnel. Helps them a lot to tuck in their belly and have a rounder jump.
Hello Robyn Hofmann
One of my pony's used to rush to jumps and kinda go straight over the jump not bending very much. What I did was place rails and landing rails. So put one pole one stride (make it a little tight because it will make a better bend over the jump) before the jump and one pole one stride after. Squeeze and sit super deep right before the jump and the get into 2-point, so the horse can learn to bend over the jump and not just jump straight over(most likely your horse is taking a long spot). You can also jump wide square oxers. Your probably going to have to experiment a bit to figure out what works best for your horse, but these may help a bit. Hope this helps!