All good tips here. To summarize:
1) make sure joints are at different locations, but close to each other
2) slip correct size shrink tube(with sealer inside) onto 1 of the wires of each pair and also slip a piece of tubing onto all 3 pairs to use to cover all joints
3) twist a pair together with cut end of each wire meeting insulated covering of opposite wire
4) heat soldering tip until it melts solder easily
5) place tinned tip under wire joint
6) place solder wire on top of joint
7) when solder melts and is "pulled" into joint, remove soldering tip
8) let jint cool
9) slip shrink tube over joint & heat until sealer begins to show at ends of tubing

Repeat for next 2 pairs

Break out a cool one and admire your handy work

 

...and make sure it's far enough away so the heat from the solder gun and the wire does not cause the heat shrink to prematurly shrink in an area that you dont want it to shrink.

Cant tell ya how many times I either make the solder joint too big and I cant get the heat shrink over the soldered connection....or I have it too close and it shrinks before I need it to shrink.

ALL due to not watching what I'm doing more closely......[/QUOTE]

You can clamp a pair of vicegrips between your solder joint & your heat shrink to act as a heat barrier. This comes in handy when theres not a lot of wire to work with.