I posted this picture in a Muay Thai group and with the understanding that I was merely copying the pose from Ong Bak and not trying to keep a tight guard or anything else, I got a good tip about keeping my toes curled tight (which I did) but UPwards. My coaches have always told me to flex my shins but not the direction of my toes.

Also on an unrelated post about roundhouse kicking: "This might be weird to try, but really try to pull with your standing leg. Not quite a jump, but more of a pull! Try it"

Just thought that was a good cue. Seems like thinking it will help with balance.