I’m watching the rider and what their position looks like and watch how they prepare for the jumps.
Hi, for me when I am watching a horse jump I’m looking at the riders balance, if they are pulling on the bit (because they should be releasing over the jump). As well as the horse and the riders approach to the jump, if there is hesitation by the horse or rider if they are jumping long or deep, etc. But I think that everyone has a different way of looking at a horse go over the jump and different people look for and notice different things.
I think it is important to pay attention to the riders presence on the horse, their balance and how they are connecting with the horse. I also think it’s important to see the horses temperament, if they are willing, trying to avoid, or blowing up.
When you are watching a horse jumping a course, the first things to look at are the horse's temperament, his general condition such as his muscle structure, his ability to accept the riders demands. Then, the horse's style over the jumps is important but I make respect and good behavior my first choice.