1) Don't come on too strong- nothing worse than making her feel trapped in a relationship.
2) Don't not come on strong enough- she wants to know that you care about her (yes, I know that is a contradiction, but the female mind is a complex thing)
3) VERY IMPORTANT- learn to read her mind! Seriously, the number of times a girl I have been with has expected me to know exactly how they feel despite them repeatedly saying the exact opposite. Classic example- you ask 'are you ok?' if she looks upset, and she replies 'fine' that actually means her entire family died in a car crash 10 minutes ago and she thinks she is fat...
I once got caught with 'it ok if you don't come round later?' to which I replied 'of course, I'll get some work done instead'- she did in fact want me to come round as she was miserable and proceeded to spend the next 20 minutes telling her friend what a heartless monster I was (until the friend told me and I came round...). I am no longer with this girl...
4) (the serious answer) There is no way to make a girl love you back, it just doesn't work like that. All you can do is be yourself around her, make her feel loved, and above all else BE HONEST. Honesty comes across better than anything else- let her into your secrets, tell her openly if there is something (small) you don't like about her (maybe you'd like her to grow her hair a little longer etc.). She will respect you for that, and hopefully open up in return. The more honest and open you are the closer your relationship will get, and the more likely you are to keep her. And even with all that it may not work out, some things just aren't meant to be- don't EVER think about that though, focus on the good things and be confident that the relationship will work- worry leads to paranoia, which will lead to it falling apart you faster than you can blink!
And I agree, sex isn't important when you really care for someone- make sure she knows you feel like that, but still have plenty anyway (and remember, give more than you take... they like that).
/serious answer