Compliments can show confidence if they're done in the right way, after all, a lot of people simply are afraid to tell a girl they think she's nice looking.
Obviously if you're drooling at the mouth whilst complimenting her, she's probably going to think you're weird, as well as being a wuss.
Just the same way as if you always succomb to little tests like,
"I am I better looking than her?"
I made quite a good compliment the other day actually, I was talking to a girl at College about hot celebritys, and she asked me if I preferred Britney Spears or some other singer, can't remember who.
I said Britney because I prefer blondes, the girl who I was talking to was a natural blonde.
It got a straight reaction as well, smiling and blushing.
This paticular girl had actually being asking me previously whether or not I thought she was nice looking, I never gave her a straight answer so she was more desperate to know, I suppose.
If you make girls work for compliments then you'll find they're far more appreciated.