My friend.

Compliment her constantly about her hair. Ask her questions about how she takes care of it, etc.

Think about it. If someone complimented you about something about your looks, you would be focusing on it constantly.

Eventually, ask her if it would be OK to take her picture. Just that.

As she poses you can ask her to do things with her hair and she is likely not to notice this.

If you really fall for her and her for you, she'll do anything!

Good luck and keep us posted!

tg