I'm 12 years old and I really like this boy, I want him to notice me. But I don't want to over do being cool or I'll make a big fool of myself. How do I make his jaw drop from being cool. It can be sayings, action etc; ANYTHING THAT WORKS BASICALLY!!

Cool is short lived, cool is shallow, cool is what people clump around thinking they are supposed to.
What attracts guys to girls isn't that different from what attracts girls to guys - niceness.
You will SEE mean girls and mean guys with friends hanging on their every word, but it's fake, and it doesn't last any longer than a song stays # 1.
So say little compliments and friendly interested things as you pass by, and keep walking.
Don't get too personal and don't plant yourself in front of him.
You might go 2 weeks just saying Hi or Wasn't that exam awful, and if he totally ignores you, that's your clue to not go the next step.
If he responds, then you say Hey I like that shirt or Do you think you'd ever join the orchestra.

Hi...
One thing u should never do with a guy,"Being someone your not" If you want him to notice you be friends with him. It isn't scarey as I thought it would be.. Just try to be funny okay.. He would like you for you not someone else... (:

He's a boy, not someone from another Planet. Talk to him the same way you'd talk to a girl - with subtle differences. There is no "sure fire" way to make him like you or notice you or ask you out.

Befriend him, and be as you are. He will eventually be a very good friend of yours, and at the right age, who knows you both might strike a different level.
I don't think you can make his jaw drop unless you do a double back flip.

Do your parents know you are trying to do this? Do they allow you to have a boy-girl relationship?

Before you try to grow up too fast, enjoy your childhood.