There are various ways to ask someone out. You could use the Six-Word technique;

"Will you go out with me, Evans?"

"No."

The PPW (period per word) technique;

"You. Me. Date. Together?"

"No. Never. Ever."

The Stand-Tall method;

"EVANS, GO OUT WITH ME?"

"No. Get off the table. 5 points from Gryffindor."

The Quicke method;

"Will-"

"No."

The Ask-A-Friend;

"Sorry Lily but will you go out with James?"

"Sorry Remus but not until the world burns."

"Right then."

The It's Chirstmas! method;

"You know, they say when someone kisses another under the mistletoe they're meant to be!"

"No, Potter."

"Wait- come back!"

The Send-A-Note method;

Dearest Evans,

Will you go out with me?

Write back,

James.

Dear Prat,

No.

Don't EVER write back,

Lily.

The Declaration method;

"LILY EVANS, GO OUT WITH ME!"

"JAMES POTTER, NO!"

And finally the Fool-Proof method.

"Go out with me?"

"We're already out."

"That's why it's fool proof."