A while back I built an AD633 ring mod guitar pedal from Mad Bean Pedals (Freekout) which sounds great, so I had a look around for a Eurorack version and came across this simple schematic on the Music Thing Modular website: https://musicthing.co.uk/building-an-ad633-ring-modulator-module/
For small projects I really like David Haillant’s Eurorack stripboard, as it has a layout for reverse protection diodes and decoupling caps, a 10 pin power header, and has a ground strip running down one side and +12v/-12v and GND running down the other.
The layout for pots and jacks he uses is for horizontal components, and most of the stuff I have on hand is vertical (thonk jacks, alpha pots, submicro switches etc).
A simple way of getting round that, and having something for the panel to attach to, is using 90 degree / right angled 2.54mm pin headers soldered to a small perfboard strip like this:
Saves a load of flying wires.