How to keep straightened hair good?

Okay, so I'm a guy and I am asking about hair, but you gotta understand I have really bad curly hair. And its not like a good curly like the kind that girls like. Yet I have straightened my hair several times before and when I do it actually looks good. The problem is keeping it the way it looks when it is freshly straightened. For example the other day I was going in town to meet some friends and I had some time on my hands before. So I straightened my hair before. One friend said it was a lot better, but after walking in the wind for like ten minutes it began to expand, and push out on the sides. It looked very expansive and caveman-ish after that. Does anyone know a solution to this?