I have to second all the "sleep in braids and try Johnson's no more tangles...greasy- so she will have to shower more often- but it works splendedly"! Also teach your daughter to brush from the ends and work up...no combs until it is brushed out...and try a big brisle brush- i use a Vidal Sasoon Vent Brush- works great- or a pick to start through first before using the brush!
As far as a hair cut, I have VERY thick, naturally wavy hair and HATE short cuts...makes my hair too poofy! Anyway, I get a shoulder length cut with long layers (short layers will just add poof too)...my stylist always thins it a bit which helps with the weight, but still looks thick. The shoulder length seems to bring the curl out the best...any longer and it pulls the curl out. As far as styling, I wear it in a pony tail (either all the way pulled through or pulled 1/2 way through) or if I need a little more dressy, I just throw some mousse in it while it is still wet, scrunch and let it air dry (or you can blowdry it a little...keep scrunching though)...man, do the curls come through! I'll also put it up in either one barrette or 2 barretts on the side...you will have to expiriment with the size of barrettes needed to fit in your daughters hair without being too big for her head!
As far as stylists, I would avoid the "cheap" places like the plague (like Fantastic Sams, Cost Cutters- I got some of my worst hair cuts there- don't seem to know how to cut wavy hair...went in once for a shoulder length cut and each time she measured, one side was longer than the other, so by the end, it was up to above my chin and I was in tears for days!- also if YOU cut her bangs in between cuts or when you go in for the cuts, ask them to cut her bangs dry because with wavy hair, they will wet the bangs down, pull them straight and cut them to the "appropriate length" but when they dry, they will be VERY short...frustrating!!!) and try a place like JC Pennys or another salon or ask friends with thick hair who they use and if they like them- keep trying ones until you find someone you love...will make all the difference in your daughter loving and embracing her beautiful hair!