Key to this is composing a shot with a foreground object prominent in the frame and off to one side, so you don't have to mask out the entire object, just one side. The effect can be intensified by adding some scaling to the background image, but that's not absolutely necessary to achieve the sense of 3D. Also, a subtle movement is all that's really required---less is more in this case.
Though the "down and dirty" (one side only) is quick and easy, the little details is what either convinces or not, and people are really used to very good video and will pick up on that, even if subliminally. It was very obvious to me, and I don't even have the best eyesight. Just my 2c and worth every dime.