Be yourself. Act confident, smart and comfortable with your own skills and abilities, whether you are good at fixing things around the apartment, playing sports or knowing tidbits of historical information. She is dating you and likes you.
Realize she is dating you for your personality and stop obsessing over your looks. Show your girlfriend your sense of humor by lightening the mood if the car breaks down in the middle of nowhere or if the waitress accidently spills a pitcher of pop and it lands on your new pants. She'll appreciate that you can let the small things go and that you still crack a smile as long as you are having fun with her.
Take your girlfriend's feelings into consideration and act like a gentleman. Stay involved in your own interests and activities as that helps make you more confident, but discuss options with her so she is involved in some of the plans.
Celebrate both of your successes together. Learn to accept compliments gracefully from your girlfriend by making eye contact and smiling while saying, "Thank you." Realize that it is acceptable for your girlfriend to be promoted and make more money than you do, and celebrate her success by telling her how proud you are of her. Remember you both like each other, no matter who makes more money.
Learn her kissing cues. Kiss her sensuously and longingly if she starts out slow and let the kiss linger, however kiss her more aggressively and playfully if she begins with a passionate kiss, according to William Cane, author of "The Art Of Kissing."