I would claybar the car well. Rather than follow the directions on the clay, I use a bucket of very clean water with car wash soap added. I then use one of the fuzzy wash pads which makes the clay easier to hold. On black it is very important to clay first as it removes any imperfections and old wax and makes the paint like glass. I doubt you need to use any paint cleaner but you should clean the entire car with detailing spray and a MF towel before waxing. Then lay on a couple nice coats of quality wax. I use a wax called Collinite #845 Insultor Wax. It isn't exactly car wax as it was developed for treating high tension power wires and connectors, but it last a very, very long time. I always finish by rubbing the car down with McGuires Ultimate Detailer.
My wife had a black car for awhile and after that, I said no more black cars. They look fantastic when clean but it is very difficult to keep black clean.