Be you. As silly as it sounds guys like a cool, down to earth girl they can have fun around. if you try too hard to impress him he'll be turned off. There's no such thing as leagues you just have to work on your self esteem as hard as it is, we gotta get some confidence girl! Also do the give and take.. show interest and then pull away, that can sometimes get someones attention quite well. .Guys who are nice don't usually think in the "oh yeah I can have whoever so ill go for the hottest one" mind frame... unless theyre' shallow and not the kinda guy you need... so be you and he'll be attracted by your personality if there's chemistry there.
First of all there is no such thing as leagues, so go ahead and get that out of your head.
The most important thing is for you to be your self. But some tips to grab their attention are, wear sexy clothing, like skin tight T's with skinny jeans or a short skirt. Joke around and be a little sarcastic with them. Don't be afraid of touching them, like a hug or hitting him on the arm every now and then. DON'T BE AFRAID TO BLUSH! Guys love it when they can get a girl to blush at something they said or did! Text/call him every now and then.
A really good way to hug someone you like: put one of your arms up to his shoulder blade and the other just above his waist/lower back. Get up and close and pull him even closer. Put all of your weight onto one leg, and lift the other one up just a little. Like 2 or 3 inch's so its just noticeable.