For Osprey Games’popular Frostgrave rules, here’s a tutorial on making snowy pine forest bases.
terrain
Making Incidental Terrain
Incidental terrain are those small bits of bush, rock outcroppings, and other features that serve to break up the look of a flat gaming table. The Battlefields and Warriors blog has some tips on creating battlefield incidentals. I really like what he has done and realize that I don’t have enough on my own tables.
Making Magnetic Terrain
Dux Humunculorum has a post on making magnetic terrain. The idea is to keep your bases from slipping off the slopes.
Making Terrain From Cardboard
Although this video is focused on Warhammer 40K, I think the techniques shown for building terrain entirely out of cardboard are worth studying.