instead of letting her choose where when and how to punch have the guy holding the mits move them around. she strikes whichever mit is open to her. guy stands with the mits facing himself. if the mit faces her directly she jabs at it wherever it may be. if it faces the floor she uppercuts it. if it faces to the side she does a hook with the opposite arm. make her guess when and where to strike and then try to strike as hard fast and contrlled as possible
my gf wanted ot try boxing so we got a pair of gloves and a pair of mmits and i train her this way. i move around like im boxing with her and will occasionally throw a punch with the mit and she has to duck or back away when i do or else she gets hit.