Here's a 40mm base from GW's Fenrisian Wolf kit. I've started off by gluing some railway ballast, and some broken coffee stirrers, using white school glue - good ol' PVA. To seal it, I've sprayed it with acrylic black and while the black was wet, I sprayed a light dusting of white for highlights. Nothing special here, nothing fancy.
Now that's the end of using paint for these bases. The rest is all achieved with powders and basing materials.
Tamiya's weathering compacts are amazing. Here I've used a combination of sand and light sand, dusted and scrubbed over the woodwork (not worrying about the gravel overspill)
Next up - PVA painted painted or scraped with a spatula over the gravel. Cheap and nasty green flock provides the underlay - it's essentially moss, but left alone to dry, it looks like Action Man's hair.
While the glue is wet, grab some static grass and dab on over the flock. This provides some texture, colour variety, and hides the nasty mossy cheapness that's providing the main fill. Don't waste expensive static grass to fill larger areas - this costs less, and looks at least as good.
You could leave it there for a simple autumnal scenic base, but these doggies are on Hoth or somewhere just as cold, so they need snow and slush to stand on. Woodland Scenics make a product called Realistic Water, which, naturally, is great for water effects, but when mixed in a 60-40ish ratio with the Army Painter's Snow Flock, it creates a nice paste makes fantastic snow drifts.
For slushier areas, use a wetter ratio, or drip neat Realistic Water to melt holes in the paste.
Once spread, sprinkle some Snow Flock neat over the top, shake off the excess, and set it aside to dry.
This tutorial took about 30 mins to build and photograph - after the initial glue and paint, which was about 5 minutes' work, and an overnight dry. If you're not prepping bases for pictures, you can do this in half the time...
Go get creative!