i like green/hazel eyes the most but honestly every eye color can be really pretty. as for the hair I like darker hair more but it wouldn't make or break my attraction to a girl. just keep your hair clean and looking nice, the color doesn't matter that much.
I don't know about the hair, but almost nobody really cares about the colour of eyes. I've seen people who've been together for over a year but can't tell the colour of their partners eyes without looking :p
Whatever works with the girl. As long as the hair is natural. Generally blondes go very well with blue eyes. Brunettes go well with green/hazel/ and brown eyes. And black usually go well with brown and black eyes.