Most Helpful Guy
This is too difficult of a question to answer since A) I don't know what you look like and B) what I find attractive in a girl may be unattractive to another guy.
You can't generalize attraction.
It's like me asking: Hey I am kind of funny how do I become funnier! When there are different people from different cultures with different sense of humor, like feminist humor may make one giggle and another frown.
Get my point?
But if ya want a general answer to your general question you become more attractive with a smile.