Just dropped my son off at college over the weekend, the advice I gave him:
1.) If a girl invites you into her dorm, at the very least she trusts you. Most likely though, she likes you. Don't be too aggressive.
2.) If she makes eye contact and holds it for a 3-count, start to go in for a kiss. If she makes eye contact, looks away, then makes eye contact again, start to go in for a kiss. If she makes eye contact and smiles, start to go infor a kiss. Don't be too aggressive.
3.) If you two are standing while kissing, slightly and softly touchh her arm just above her elbow for the duration of the kiss. Alternatively, if it is a passionate kiss, gently pull her closer by the small of her back.
4.) If she is laying on top of you while you two are kissing, touch her butt. Don't be grabby at first, she'll let you know.
5.) If she stops anything you do or pulls away, she doesn't like it. Stop what you are doing.
6.) Make her laugh and feel comfortable. Do not make her laugh at other people's expense though, that cones off as dickish and is a red flag.