This is a basic unshielded twisted pair.  This topology has been around a long time, and is extremely materials sensitive.  I recommend Kimber TCSS hookup wire, as it uses multiple strand sizes within its construction, reducing the effect of mechanical resonances.  Strain relief is accomplished via Radioshack self-sealing silicone tape, the orange stuff (it's an in-store stock item at this time).   RCAs are Dayton WBT clones from Parts Express.

Kimber TCSS wire can be acquired from Welborne Labs,  an excellent parts supplier, and a sponsor of the Audio Asylum.  I recommend you use their house brand silver solder, as it's easy to work with and sets up nicely.  Both WBT and Cardas solders are also a pleasure to work with, but the Welborne is very nice, and more affordable. 

Purchase 4.5X as much wire as length you'll need for 1 pair.  So for a 1M pair, buy 2.25M in white, and 2.25M in black.  These colors sound better, believe it or not.  Cut the wire into lengths, about 1.1X the length you need your finished ICs to be.  Then take 1 white and 1 black wire, and twist them together, about 1 twist every 2 inches.  you want the twisting rate to be consistent, and not one tight twist followed by a length with no twisting.  This way the cables hold together with no need for a performance robbing jacket.  Repeat this twisting again, and you'll have 2 lengths of twisted pairs. 

Remove the locking cover for the plug, and run the end of the twisted pair through the back of the connector and up through the opening so you have room to work.  You then should strip the end of the white wire for termination- be careful, some of the strands are very small.  Strip only enough to fit into the terminal cup for the center pin, and solder it in.  Then you want to attach the black wire for ground connection.  You want to do this by stripping 1/2 inch, then separating the strands into a sort of fan, and folding half of this fan over the edge of the connector, as close to the contacts as possible (far towards the pin).  Use a pair of pliers to squeeze the fan on both sides of the connector barrel so that it holds in place. Now solder this on.   I recommend a solid 40W iron for this, a 20 watter won't heat the barrel fast enough. 

You will, of course, need some strain relief, if there's a chance of the cable being pulled on wrong.  For this, you want to back out the set screw in the plug so that it doesn't penetrate into the inside of the barrel.  Then tightly wrap the stretchy self-sealing silicone tape around a section of the cable- you want this wrap to be the same width as the tape.  This section should be sized to fit inside the threaded portion at the back of the connector.  Once you've wrapped enough tape around to do this, slide it into the back of the connector.  It should be a tight fit.  Now screw the set screw into place.  This should provide a reasonable amount of strain relief. 

Repeat for the other 3 ends of the cables, and whalah.  You've got a great interconnect at a reasonable price.  Any cosmetics are up you, if you want a techflex cover, order some with the connectors, and get some 1/2" 3:1 adhesive lined heatshrink to hold it at the termination.

I recommend you not use the locking covers, and just leave the connector open, but that's ugly, so use your own judgement.

Power Cord

This is another twisted pair based design, twisted pairs being an ideal geometry for the diyer, having great properties, and being easy to make to boot.  For this I recommend going to the Home Depot and getting 3  50 ft. spools of stranded THHN wire in 14 awg.  Get white, black, and green.  Cut a length of each off the spools about 1.1X the length you'll need the PC to be.  Twist the white and black together as with the IC above, then wrap the green around it so that the green crosses the other two at right angles.  Use some of the Radioshack self-sealing silicone tape to hold it together.  Then, you need to terminate.  I recommend using Marinco Wall Plug and WattGate IEC 320 from Parts Express.  Green is ground, white is neutral, black is live.  IF YOU DON'T KNOW HOW TO TELL WHICH IS WHICH ON THE CONNECTORS, READ UP ON IT.  SAFETY FIRST.

Use a little of the silicone tape and the stock strain relief to provide strain relief. 

I recommend using caig ProGold on the stripped wire before terminating to keep it clean.  Also, you may wish to find a torque screwdriver to avoid overtorquing the connections- be very careful not to overtorque them.  They come with instructions regarding termination, follow them. 

These instructions are a little more basic, as if you can't extrapolate anything else you need, you shouldn't be building DIY powercords yet. 

MORE TO COME.