This horse (My Maxwell) is in a fairly good frame and balance, but he appears slightly hard on the bit because of his dry mouth. Foam isn’t necessary to show softness, but some form of saliva shows that the horse is chewing the bit.
The rider (Molly Paris) shows a fairly dramatic cock at the wrist; the knuckles are almost pointing toward the ground when they should be pointing toward the horse’s mouth. The elbow-to-bit line would be nicely straight otherwise.
Because her seat is a little weak and tight, the rider appears to be sitting “on” her horse instead of “in” him. So I suggest she do her whole ride (after warming up) without stirrups. This encourages her seat to be heavy and lets her legs hang underneath her. The perpendicular line (aligning the ear, hip and heel) is too far forward. By making her leg hang longer, riding without stirrups should also allow her heel to come down because the stirrup prevents her toe from hanging. I would often remind her to loosen her thighs and let her seat sink down. Her upper body is very straight and upright, revealing good core strength, however, she is looking down instead of where she’s going.