I wanna dress like Blair for gym, does anyone know how i can get the look she did in the episode she played lacrosse?

Well it all depends on what your school will allow. Do anda have to wear a uniform? Does your outfit have to be a particular colour? Can anda wear a skirt?

If anda have a uniform it will probably consist of a polo top. If anda dont, anda can always buy one fairly cheaply and in heaps of different colours. Polo tops are great for sport becasue they are so comfortable. Blair wears hers buttoned up.
link

Blair tucks her polo bahagian, atas into a sports skirt, which anda can also get in a range of clours and styles from sports shops. Blairs skirt is very short, so anda would have to also get maybe short bike shorts to go underneath.
link

Blair teams all this with High socks: link
a wide belt: link
sweat bands:link
And a neat, pulled back hairstyle:link

I dont think anda see her shoes, but I think this is the one time when she does not wear heels :]