I try to keep my rates mid-range, since I am newer and am still establishing myself. So I don't go to the lowest end of the scale, because I am shooting for a specific clientele no different than anyone I'd interact with on a day to day, and I don't go to the highest, because I cannot provide luxury services like incall, overnights and extended trips. Base your rate on what you want in your clientele, what you are willing to offer, and the rates in your area.