I recently took my FTM partner to get his hair cut for the first time in a LONG time (does it himself usually). He hasn't done anything to transition yet, and is pretty androgynous but assumed a woman. We went to Great Clips and just asked for it to be cleaned up, shorter on the sides and longer on the top. About an inch on the sides and an inch and a half on the top. This was in a pretty conservative part of town, but the hairdresser didn't even blink an eye and was very sweet making sure it was just what we wanted. No big deal. Just go in with confidence, knowing what you want, and tell them what you want done. They shouldn't even think twice.