Make365 - Poorly Made Arcade Cabinet

I cut out the pieces for the tiny arcade cabinet and started putting it together. It doesn't fit right. The final assembly, which isn't pictured here, looks like a shanty town shack. It's all crooked and, well, ugly.

I learned a few things:
1. Cutting free hand leads to pieces that don't really fit. I need that mitre / fence.
2. The 2" wood blocks I bought are close to being perfect squares. But the difference really does make a difference in terms of putting it all together.
3. I'm going to redesign it some so it's easier to cut and assemble.