Raise your hand, all those who’ve forgotten to do these things:
- Run ERC on the schematic and DRC on the board
- Check to make sure no op amps have reversed inputs (if there’s a feedback path from output to + input, it’s probably wrong)
- Check power connections to chips for reversal
- Check orientations of polarized caps and diodes
- Check capacitor footprints for lead spacings and body sizes
- Check pots to make sure they’re not connected backwards (usually pin 1 to the lower voltage if a voltage divider; usually pin 2 connected to pin 3 if a variable resistor. Usually. And those are if using footprint where pin 1 is counterclockwise, which is not true of some footprints, so check that too.)
- Check pin headers and sockets to make sure connections are consistent on both sides
- Do track cleanup (KiCad PCB tools menu)
- Make sure silkscreen isn’t garbled with e.g. references/values on top of each other, off the edge of the board, on top of a pad, etc.
- Check connections and orientation of board mounted toggle switches
- Check if adequate information shown on the silkscreen. Maybe your name, credit to circuit designer, license information, GitHub URL…
- Is there anything confusing about the build that could be mitigated with some notes added to the silkscreen?
- Check mechanical matching between sandwiched boards, board and panel, etc. — do mounting screw holes line up? Headers/sockets? Board mounted components and panel holes?
- Check for adequate clearance on all four sides of PCBs, allowing gaps between adjacent modules and allowing enough space at top/bottom to mount the module
- Verify everything routed
- Verify all fills updated and filled
- Order number location marker on silkscreen, if appropriate
- Look at the Gerbers in a Gerber viewer to verify they look right