how to buy power cords that fit my components (i.e tight and snug)

Rather than focus on what will not improve sound, and maybe make things worse, why not address the root cause of the problem? Support power cords so they naturally lay where you want them to be. That way not only is there no stress on the connection, but when properly supported there is much less vibration in the cord, and far less being fed into the component by the cord. Until and unless this is done then making the plug fit even tighter is making things worse not better.

Millers right, I have a block of wood under the connector going into my amp. 

If it's a PC you like and want to keep it in your system, wrap Teflon tape (plumber's tape) around the loose-fitting connector. Electrical tape will eventually become sticky and leave residue. I have two cables wrapped with Teflon tape and no problems.

And I agree with using a support under a cable that sags. Some cables fit tightly in the IEC but are heavy and could use a support.

Listen, if you absolutely insist on shimming it up to fit tight, at least have sense enough to ignore the awful electrical or teflon tape advice. Electrical tape is soft and squishy and the adhesive never hardens so you wind up with a goopy mess. Teflon tape is designed to be slippery, the exact opposite of what you want. So if you must- and again this is not the way to go - but if you must then use heat shrink tubing.

But what you really should do is support the cable, preferably with something like a cable cradle that both supports and isolates, in such a way that it will stay put even without having to be crammed in so tight.

@audiocanada - Try the aluminum foil tape (Home Depot) used on heating ductwork.

A couple of small pieces on the underside of the plug should be adequate

• it is not spongy or slippery
• just make sure it does not extend past the end of the plug and touch the pins of the socket

ALSO - support the cables as stated above

It’s not really about how tight the plug housing is, but how tight the pins are gripped by the IEC socket that matters

I make my own PC’s and use Sonar Quest silver palted copper connectors, because they grip the pins like a vice.

Good power cables will generally have pretty good connectors

Hope that helps - Steve (Canada)