1. Tickle her. She'll love it even though she tells you to stop.
2. Forget diamonds! Hugs are a girl's best friend. She loves them...especially if they are from you.
3. Spend time with her, even if it's time just sitting not doing or saying anything. Your presence is enough.
4. Hug her and tell her she looks beautiful when she thinks she looks like crap.
5. Tell her she's cute/pretty/beautiful whenever you can. She likes getting compliments even when she says she doesn't.
6. Hold her hand or wrap your arm around her. She likes it when you touch her.
7. Laugh with her, not at her. And if she thinks you're laughing at her, hug her to reassure her you're not.
8. If she's cold, wrap your arm around her or give her your coat/jacket/hoodie. She will think you are the sweetest thing in the world even if she already does.
9. Short kisses on the cheek/forehead/neck are always sweet. They let her know how much you care without being overly showy.
10. She's nervous around you, so you both are in the same boat. Yay mutual nervousness!
11. Tell her you care, no matter how you say it.
12. Be yourself as much as possible. If you're not, she'll think you have something to hide.
I just realized that when I'm thinking really hard about something, I avoid eye contact and get really really quiet. I also bite my bottom lip.