Hi,
I hope, along with the above great advice and recommendations, some of these may help.
I only know about keep return paths as short as possible, is one, that's good to learn about for layout; and then the above of separating the board into sections (imaginary quadrants, let's say), not mixing analog and power or digital if poss, I think I remember power guzzlers should go as close to the pcb supply input as possible, and a single ground plane, separate regulators can be helpful if possible and not too OTT in number.