I just figure there's not much to be done, except not wear shorts and a tube top.
I have an Egyptian Muslim friend who covers her hair and dresses modestly (not that I've seen anyone who covers but dresses like a skank, but anyway...) The last time she went she was VERY pregnant. Guys still harassed her! What gives? Maybe she was alone, but what kind of imbecile harasses a covered pregnant woman?
Personally, I don't support the covering of the hair in a country where religious minorities who don't support covering are regularly injured and killed, but I think it is very prudent to dress modestly :) It got me safely back from Greece (when I wasn't harassing the men myself...), Turkey, Morocco, Portugal and Spain. Despite differences in religion, countries share a machista culture. It's very wise to just take some preventive action and not have to worry about getting leered at.
Dress modestly and the men will lose interest and play with each other
