I’ve been in this hobby for forty plus years, so I forget what it is like to start out. I’ve got a lifetime’s worth of wargames terrain to fall back on. But if you’re just starting out, here’s a primer on wargames terrain that you may need to start.
modeling
Building A Ruined Defensive Wall
A Year of Frugal Gaming Blog has a photo tutorial on making a ruined wall from plywood and other bits.
Constructing Japanese Style Buildings
The Boring Mordheim Forum has a photo tutorial on constructing Japanese style buildings for 28mm figures.
Making Tree Stands From Old CDs
The Too Fat Lardies site has a tutorial on making stands for trees and other foliage from old cds.
Green Stuff Sandbags
The Dark Future Games Blog has a tutorial on making sand bags from “green stuff” epoxy putty.