Quinzees are much faster & much easier to build than igloos. We built this one just for fun, but we've also made them for sleeping in while winter camping.
Step 1: Find a spot & start shoveling
Where you build your quinzee is pretty important. If we had needed quinzee to sleep in, we would have found a nice sheltered spot, on level land. We opted to build ours on a lake instead. Now, frozen ice conducts heat much better than frozen ground, so sleeping on a lake will draw your body heat away much faster. That really sucks. Not a good choice for over-night campouts, but were just building this one just for fun, so it wasn't an issue.
Where ever you choose to build yours, start by digging out all the snow from the area that your quinzee will sit. Then shovel it all right back. Moving the snow like this will cause it to settle out and give your quinzee a good solid base.
Step 2: Build up a big pile of snow
Figure out just how big your quinzee needs to be: get everyone that you want to fit in it, to lie down in the area you've just cleared out & make sure everyone fits! Add a foot or two all the way around and that'll be the diameter of your quinzee. Easy.
Keep shoveling on snow until the base of the pile is as big as you need it to be. Once you're done, it'll look pretty conical (perhaps even comical), so feel free to use your shovels to round it into a nice dome shape.