Step 2: Plan your design and layout
Coming up with the design and layout was a bit more intensive than I thought it would be. After a lot of research on several arcade forums, I came up with a layout and spacing that seemed right to me. If you're still at all unsure of how you'd like your layout, you can always install your controls on some sort of cardboard box to test out the feel of them. Many people suggested a shoebox for testing the joystick/button layout. I followed my plans, and the controls feel very comfortable to me.
Plans for the box enclosure are pretty straight forward. I definitely made the box a bit taller than it needed to be, in order for it to sit at the right height at home. Play around with different dimensions until you find what's right for your application. Again, cardboard is a quick and cheap way to mock everything up and get a good feel for how it will look.