Every now and then you may need to add a component to an existing circuit board.
You may need to add some new functionality, modify a mistake or maybe add a marshaling point for GND or VCC.
If you have one of these inexpensive metal hole punches, punch out different sized pads from 1/32" single sided PCB material.
Use epoxy or high temperature liquid steel glue/epoxy to affix the cutout pads in free PCB areas.
After the glue hardens, solder your components and wires to these pads and your existing PCB traces.
Try a small drop of ‘Super Glue’ on motherboard and small smear of ‘Super Glue Accelerator’ on the bottom of the cutout pad.
Don’t forget about using the real estate on the bottom of the PCB.