If you're waiting for one girl to notice you, you should be hitting on another girl, a lot of other girls.
Nothing makes a guy more of a catch than the fact that another woman wants him.
This is called social proof.
So if you're sitting there, wondering where everything went so wrong, why you don't get the opportunity to date the girl you want - WAKE UP.
Life isn't fair, just like dating. Love isn't fair, just like life.
When you love somebody and they don't love you back... stop wasting those weeks, months, years.
MOVE ON and move up to another woman.
Stop WAITING for things to turn your way. STOP hoping for the CHANCE for her to see you in a boyfriend way.
MAKE things happen FOR YOURSELF.
Nobody else is going to help you if you aren't willing to make the first move towards being the type of guy that women want.