I tend to use the same method as John, drill & tap, although I always do it just before cutting the outer perimeter. I like Johns idea more as it allows for quicker production of multiple items.

But sometimes you don't want holes in the piece your cutting, so then I use tabs but can only do it in artcam, not figured it out with soldiworks yet.

I never seem to use the vice on the cnc mill, but use it all the time on the manual mill.

I also use the rotary table to hold square stock if it does not need tight tolerances and is quite short, just because is so quick to clamp etc.