Could someone please explain the proper form for strumming?

or post a link to site that explains it...

I think Ive been doing it wrong for a while now and want to correct myself before I do any more damage.
Quote by pugnapugnapugna
Well you're gonna wanna hold the pick and rake it over the strings. That's pretty much it.

Yeah, I know that part. But do you use your wrist, move your entire arm, both, or what?

The reason I ask is my elbow has started to hurt when I play for more than ten minutes and I think its because I am strumming incorrectly.