if she is just learning you need to sit down with her and see what she is capable of- what (may) seem pretty easy to you may not be for someone who hasn't much experience...i've been long-arming for over 10 years now- and still have not been successful at a good looking feather design...and it sure seems like lots of customers like feathers---i keep trying, been drawing them for a while now- and am ready to load up one of my practice quilts to give it another go---but i would not even consider doing them on a customer quilt no matter how much they would like them- i'm just not capable yet.
for a person just learning an easy-meandering all over pattern will probably give you the best outcome.