StrictlyDating is correct. Approach the girl you like with respect and honesty. Nothing turns a girl off faster than a fake or someone trying to be someone they're not.
Respect the girl's feelings - there is nothing attractive about a macho guy who doesn't satisfy her emotional needs. Open up to her about your feelings. Give her small gifts occasionally for no reason. They don't have to cost money. Anyone can put down money and pay for something. This does not necessarily mean that you care.
Try things like a poem written just for her, a bouquet of wildflowers picked by you, a note tucked in a pocket for her to find later, a picnic - get those creative juices flowing.