Bipod, telephone pole, sling, shooting sticks, fence post, tree, rocks whatever works as the sitiuation dictates.
For your daughter's situation a monopod under the butt would solve the issue. They work great when shooting prone .
Accu-Shot Precision Monopod - Mid-Range Locking (BT05) with Quick Knob Option
You can cut yourself some 3x3 square wood blocks of varying thicknesses to set under it if the situation warrants and then fine tune for elevation with the built in adjuster.
Won't help at all unless you are shooting prone or off of some sort of bench. For sitting, kneeling, standing you just have to practice a lot.