watch movies that kinda inspires you. Don't wach the romantic ones. Watch the adventurous ones. Like, amm...Into the wild, Death note etc. here's a site watch-movies.net
Don't look at the sky too much.
Try writing poems or anything...about things like a cup,cat,...u know things that doesnt get invloved with relationships.
Call a girl whom u had a crush, may be a childhood crush. and talk how things are going on and make jokes or even flirt.
dont hum songs, sing it loud!!
Get a haircut or color it. try highliting the hair.
 over with it. You wont forget her but you will not be thinking about her anymore!!
and lastly, flirt!