FIRST. For each step. You'll want to key em up. Depending on how you want the shake to be (Speed wise) put them closer or father from each other.
(Make sure to zoom in slightly before Starting the moving around of the scene. Or else it'll look noobish -_-)
Then just kinda move it around the Inside of your screen area.(once again adjusting it to go with how much or how little shaking you want)
Would be easier to explain if I had Video. But I don't so yah.