For creating the housing’s finger joints, Onshape’s finger joint feature is significantly more efficient than building a rectangular pattern in Fusion 360.
Plan how all components will be mounted together early in the design process, rather than treating each subsystem as an isolated part.
Taking breaks is important! You'll be able to see your errors and get new ideas after taking a step away from the project. Knowing when to pause and scope down instead of powering through will save a lot of headaches for the future.
If you are using an LED Display, design the housing so that the LED Matrices are close to the breadboard, because long wires would cause them to have noisy signals.
When debugging, use the oscilloscope to determine if it is a software or an electrical problem.
If you make any changes to your code or logic that might appear in more than one place, make sure to update it everywhere! Legend has it that we had our entire teaching team (Karl and 3 TAs) stuck on our bug for an hour just because we forgot to change the ADC buffer size after we added another analog input, which caused a buffer overflow, which led to an impossible behavior that was totally unrelated to ADC. (Shoutout to the entire teaching team for helping us out!)