How can I start a conversation with the guy I fancy?

Some examples and samples:
Are आप in any of my classes @ school?
Do आप like cheese?
What's your प्रिय movie?
Who do आप think would be a better President, Obama या Romney?
Do आप play football? Baseball? Basketball? Lacrosse?
Hi.
Hey.
What kind of संगीत do आप like?
What's up?
What're आप doing this weekend?
Which came first in your opinion, the chicken या the egg?
Yo.

Make him a sandwich

if u hear him say anything about something u like, for example a tv-show, movie या video-game u could always start talk to him about that.
then it won't seem like you're desperate :) u just want to talk about the awesome thing he brought up to begin with.
don't think it'll work unless u hang out in the same circles though... 'cuz if u don't it might seem wierd to just jump into a conversation, just sayin'.

Say hi and talk to him like आप would normally talk to anyone else.

Just ask him about anything

His प्रिय movie
His प्रिय reality TV show
His प्रिय snack
His प्रिय electronic device
प्रिय game
प्रिय subject
If he's in any of ur classes

.....so on