Girls like guys (that's obvious). They like a good personality, a happy attitude, and someone who will treat them right.
Girls like guys who will treat them special, different then they treat other girls. So treat them with respect. It is true that "bad" boys get lots of girlfriends but that is only because girls feel that by going out with them it is they may get in trouble by going out with them, and this creates a feeling of intrigue which they are attracted to. However if you treat a girl well then they will feel special and will be attracted to you.