Have this problem with the horse I board, try bringing a treat when you get her! Then after your done with your lesson leave and then go back out like 2 hours after, ring your lead rope and a treat! Put the lead rope on her, pet her and tell her she is a good girl, then give her the treat! Take it off and pet her then do it again! It worked a lot with MARIO!!! Hope this helps!!!
use a small ring. put the horse in it and lunge her. teach her that you control her feet. if you ask her to stop and she wont, make her keep going. if she stops before you ask, make her go faster. couple times of that and they'll learn that when you say woah, they should stand there or else they will have to work. don't use treats and bribe them. that creates bad habits