CPU? LGA or PGA? If it is PGA, you need a decent method for keeping the pins from getting bent. I've seen people stick CPUs into open cell foam with little harm. Not sure today's small pins could handle being stuck into cardboard. Then you would want that suspended so no pressure can get to it and bend the pins. Bending a flat piece of cardboard around it and taping off the ends might do it. Or a tiny box it you can find one.
RAM is pretty sturdy, and like an LGA CPU, just needs to be packaged so it can't roam around and rub against things.
The GPU should be packaged such that it is unable to move in any direction and has at least one inch of packaging between it and the outside world. Putting it in a box within a larger box is a good idea. (This is true of any heavy object made of metal)