Almost every girl has a dream guy. Often that dream guy is a montage of other men in her life and a few celebrities thrown in for good measure. A dream guy will almost never come true, but that's not the point - this is about a dream, after all.
To create a dream guy, a girl usually starts with her crush. He might be a boy in school or a celebrity. She then starts tweaking features until he is ideally suited for her. He might become taller or less bulky. He might take up the guitar or become a painter. A girl's dreams are personal and should never be limited by something as annoying as reality.