The upper body often get overlooked by students when performing leaps. There are many ways to improve arms in saute chats and leaps, but this can quickly take an intermediate leap to an advanced leap in one correction.
When I taught dance, I used to see gorgeous leaps, but they seemed unimpressive. I realized that their arms were blocking their faces and making them look less technical. Once I told them to press their arms behind their faces they instantly looked effortless and lighter. Keep this simple tip in mind when teaching leaps/saute chats in dance class! Also see How to Improve your leaps focusing on the front leg.