Step 1: What do we need?
I then snagged some thin foam which can be gotten at www.nicolecrafts.com for basically 50 cents.
Used a utility knife and exacto knife, the kitchen cutting board, some scissors, a sharpie, and a screwdriver.
The good thing about this foam is when done you will end up with some scrap that works great for lining Altoids tins or other projects like that.
Step 2: Cutting
(You might notice the color changed, because I forgot to snap a pic with the full size piece of blue.)