https://www.youtube.com/watch?v=ySuUZEjARPY ("How to achieve proper grounding")
https://www.youtube.com/watch?v=ZYUYOXmo9UU ("Keys to control noise, interference, and EMI in PCBs")
https://www.youtube.com/watch?v=QG0Apol-oj0 ("What your differential pairs wish you knew")
https://www.youtube.com/watch?v=0RyBCnowLsI ("Secrets of PCB optimization")
These are all by Rick Hartley (from GP's comment) and they are all worth watching in this order.
https://www.youtube.com/watch?v=ySuUZEjARPY ("How to achieve proper grounding")
https://www.youtube.com/watch?v=ZYUYOXmo9UU ("Keys to control noise, interference, and EMI in PCBs")
https://www.youtube.com/watch?v=QG0Apol-oj0 ("What your differential pairs wish you knew")
https://www.youtube.com/watch?v=0RyBCnowLsI ("Secrets of PCB optimization")
These are all by Rick Hartley (from GP's comment) and they are all worth watching in this order.