Generall what you want to do is have the hair style that most strongly points out your masculinity. That means, in most cases, well groomed, short hair, excluding the Ricky Martin flip. There are a lot of exceptions though, for example, guys with a wide jawline still look manly with long hair, and guys with wavy hair can grow it longer than guys with straight hair an still look good. For me, I have really curly hair, and the afro look is a pain to maintain, and takes forever to grow back if you drop it, so I keep my hair relatively short, a #1 buzz most times, or sometimes I let the top grow out and spike it. But that's only on nights when I'm going out to a party/club/restaurant. To school or work I wear a hat ****ed to one side. If you're gonna wear a hat, hairstyle is still important. I try to keep my sideburns shaped and short, so that they don't look like a mess under a clean hat, and don't neglect the back of your neck either.