Go to your local Rat Shack and pick up a soldering vice. It's a heavy metel base with an adjustable cross arm with aligator clips that's REAL handy for holding your work while soldering. Switchcraft RCA's are soldered by tinning the connector with solder. The center pin is like a hollow cup, put the tip of the iron on in and let it heat up. Then when it's hot enough, feed a little solder into the cup. When the solder starts melting into the cup take the iron off the pin and let the solder cool. This is "tinning".
Do the same thing to the back side of the strain relief shaft. Now prep the wire by cutting in to size, leaving the ground wire long (it'll be trimmed later). Same deal on tinning the wire, hold the tip of the iron on the wire heating it up. Then feed solder onto the wire (not the iron) and let it wick into the wire braid, remove the iron from the wire and let it cool. Now take the iron and heat up the cup on the center pin until the tinning melts again and feed the + wire into the cup. Immediately remove the iron and make sure the wire says still while the solder cools. If you've done it right, the solder joint will look shiny and won't have an excess of solder on it. If it looks frosty, it could be what's called a "cold" solder joint and should be redone. Now take the ground wire wrap it back around the the strain relief shaft over where you previously tinned. Heat that area with the iron untill that tin remelts and remove the iron. You shouldn't need to feed in any additional solder as the the tinning should be enough. Again it should look shiny not frosty. Yer done.
Rat Shack