DOCUMENT AS YOU GO. LIFE IS EASIER IF YOU DO THIS.
Plan to do the minimum to meet requirements first, then add bells and whistles later. Pretty much every extra element will add more complications than you anticipate.
Avoid superfluous components. The team would have saved a ton of time if we reduced the amount of buttons and lasers we had in half with practically the same level of performance.
Learn new skills as part of this project. Tackle things you've been wanting to learn but just haven't had the time to do in the past. For example: if you've never laser-cut something or soldered, consider trying it out.
Hardware:
Start mechanical design early. And make it a point to sit down and discuss it with each other so that everyone is on the same page. You should have a solid idea about how everything is going to be put together prior to any individual fabricating a component on their own.
Make enough space for electronics to fit in the enclosure.
Electronics:
If your SPI lines worked fine with short wires and then stop working with long ones, look at the signals on an oscilloscope - not a logic analyzer. Interfering signals or transmission line effects are likely at play.
Twist long wires sending SPI signals to a remote device together with a power or ground line to reduce interference with nearby signals. Contrary to what you learn in an introductory circuits class, the physical orientation of wires matters!
Verify the performance of each device you include in your circuits - variations between parts even from the same batch can cause your system to malfunction.
When multiple voltages are needed for powering devices in a design, ensure they power on in the correct sequence (and sometimes with the right timing). Otherwise, peripherals might not initialize properly.
Aligning lasers over distances much further than the spot size is difficult. Avoid forcing yourself to do this if you can.
Software:
Integrate between modules as early as possible - there will be unexpected problems! We recommend behaving as though the deadline is a week earlier.
In case you're curious, here's the music that plays for the majority of the game :)