We follow most of the above advice.
The balloons are good to,get their focus.
Be prepared to,stand behind her if there is any struggle with form. Just ask her if it is ok then put one hand over her bow hand and the other on her drawing elbow and stress pulling with her arm in alignment . Sorta pulling back,with her elbow, this will help with back tension.
Have her draw the bow to,full draw without an arrow. You'll be,able to see right away if her elbow wants to bend inward.
If this is the case the whole arm needs to be protected. A large,tube sock with the toes,cut off makes a decent arm guard.
If she has the dreaded reverse elbow work on twisting the bow hand and working the elbow out.
The bow you have should be in the right range.
Don't forget to check eye dominance.