Schematics

• Net-names, use shared labels when components on schematics are not close together or when drawing a wire would be too messy.
• Avoid wire cross overs. The fewer the better.
• Don't run wires over components. Few to no exceptions for this one.
• Higher voltage at top, lower voltage at bottom.
• Inputs on left, Outputs on right.
• Align labels with parts
• Rotate components

PCB Layout

• GND is critical and must be either wide traces or a good plane.
• Power is next most critical and should have a bypass cap next to each load and should also use heavy traces or planes.
• Primarily horizontal traces on one layer, primarily vertical traces on other layer.
• Short traces are better - Frequency of signals?