Proper technique greatly reduces the strength and energy output required to do a press handstand. Most gymnasts will try to rush to the handstand lifting their heels early causing the press to planche out making it very difficult to excecute. Work presses against a wall. Start so that when the gymnast leans forward their shoulders will push against the wall. This enables the gymnast to work through the motion with some assistance.
Work presses facing away from a wall.
The gymnast should stand with their back against the wall and lean forward to press, trying to stay as close to the wall as possible. This forces the gymnast to lift their hips. If they lift their legs too soon they will kick the wall. Do a lot of presses. Ensure that the arms are kept straight.