Originally Posted by JosieAmani
I'd get them do some balancing exercises while riding bareback (eg. Touching their toes, lying back on the horse, things like that - while the horse is held and standing at the beginning), this would not only help them get some balance, it would also build their confidence and build some muscle. Once they've progressed and achieved good balance you can have them do the exercises at a walk on the lunge. As you probably know it's all about balance! Good luck!
I totally agree with getting them to do a lot of bareback work. I have a friend who when she was young (I think 5 or 6) she took her first lessons and her coach wouldn't let her even touch a saddle until she had developed a nice seat and balance to walk/trot comfortably bareback. To this day, she has an amazing seat and is incredible bareback.