Transitions are key! walk to trot, trot to walk, trot to canter, canter to trot, walk to canter, canter to walk, etc. transitions within the gait (slow trot, fast trot, slow canter, fast canter) are also great. Do lots of changes of directions as well as bending exercises such as serpentines, figure eights and circles. Do hill work if possible and lots of poles and raised pole work. All of these will help her learn to use her body properly and drive from the back end forward, which will result in getting off of the forehand. This will take time but it will be worth it! In the mean time, when she drops her head too low, simply raise your hands and push her forward with your legs. Think “hands up, leg on”. Hope this helped!