This tutorial on how to make miniature trees easy is cheap to do and simple to follow. I use twist ties as the core of the trees and then add details for a nice finishing touch. This is a great and cheap way to get some nice tree terrain for your wargaming table.
This is a tutorial on creating custom rubble bases really simply with just three things. You can really crank these out in little time. It really adds some great visual interest to your miniature bases with little work.