My first Diorama attempt

I've always wanted to try my hand and making a custom diorama, but to be honest I've never thought I have enough patience or skill to do one. Today my wife and I needed to stop into Home Depot, so I decided to bite the bullet and by a 4'x8' sheet of styrofoam, the kind you see carpenters use to insulate houses.

One of my biggest problems has always been that I rush into my projects and try to accomplish the entire thing at one time... I want this to be different. So far I cut two 20"x20" squares - one for the ground, one for the actual wall. It's very very basic right now, but my plan is to work on it a little bit each night after work until it's completed...

Suggestions are definitely welcome... This is going to be a huge learning process for me.