Not a thing I can add to that other than insulate yourself from the floor of the cave as best you can. Bring the thickest sleeping pad you own.

Personally, I find that the lack of good packed piles makes it harder to make a proper snow cave than it is sometimes worth in terms of time spent looking. I usually make a snow trench- exactly what it sounds like. Insulate the bottom, put supports across the top, then more insulation, and pile snow on top. Not as warm, but if you can't find a proper snow mound it is a lot better than nothing.

You can find hollows as was mentioned under trees with low branches, I like spruces myself for this because they go so low to the ground. But you need to be super careful if you have any kind of flame- remember, it's an evergreen full of pitch!! That has the potential to turn into a great signal fire, one that runs and screams and flails about. :P

In any case, signal markers are critical! Orange, red, blue, any neon colors, these show up pretty well. A pile of snow looks like, well, snow from any significant distance.