PCB Layout Guidelines
Hobbyists, students, even engineers tend to pay more attention to circuits, the latest components, and code as important parts of an electronics project, but sometimes ignore a critical component of electronics --- the PCB layout. As a Chinese saying goes, well begun is half done. Good PCB layout plays a great important role in your PCB projects, because poor PCB layout can cause function and reliability problems.
Ground is Not Ground: Cause ground is not an ideal conductor, so carefully route noisy grounds away from signals that need to be quiet is really important. Make ground traces large enough to carry the flowing currents.
Via Size: Vias have inductance and resistance. If you’re routing a trace from one side of the PCB to the other and need low inductance or resistance, use multiple vias. Large vias have lower resistance. This is especially useful in grounding filter capacitors and high current nodes.
Distance between Traces and Mounting Holes: Keep enough space between copper traces or fills and mounting holes can help prevent shock hazards. Solder mask isn’t considered a reliable insulator, so take care that there is distance between copper and any mounting hardware.