Never compliment a woman about her looks.
Never say “You are beautiful” or “You have beautiful eyes” etc.
She has heard it hundreds of times already from lame guys with no game, and what does that do? It marks you as a ‘lame guy with no game’.
If you compliment a woman, let that be about something she had to take some EFFORT to accomplish.
If you notice she’s got a green top, green skirt, green ear-rings etc. – compliment her on the fact that she’s well co-ordinated. That makes her feel much more special than a compliment about her hair. And chances are, she’s never heard it before.
Remember : Safe is risky, risky is safe.