Ladies (mainly 18-20): what am I doing wrong?

My response is that despite your looks/personality, if you come off as a guy who is only out to get some or date, you will have a hard time. Girls also respond to guys that are genuine and are interested in their lives and not just their looks. So if you start by building a friendship, even for just a day, you might find that you get more girls and will have a relationship that has deeper substance because your relationship will be built off of more than attraction and physical looks.