7- Use negative hits
You might use a compliment in your initial contact, but that should be it for a while. After that, mix in a few negative hits, especially if she's good-looking (which, if you're hitting on her, she must be, right?), just to keep her honest and her ego in check.
For example, "I guess you're trying to join the (insert celebrity name here) club when it comes to hairstyles. I've seen a lot of women with a similar style, but I must say it suits you a lot better than most."
Note that a negative hit is not the same thing as an insult. It ends on a somewhat positive note, but lets her know you're no pushover. After you've piqued her interest this way, you may permit yourself one showstopper compliment to let her know what you think. But if you start adoring her, she will feel she can take or leave you. Don't over-compliment — it'll kill your chances.