Soldering is actually easy if you remember 2 things. Keep the tip of the soldering iron tinned with solder and clean!!!
A 30 watt Weller iron works well! I've been soldering my own stuff since I started with electric planes 4 years ago.
Tin your iron, then apply the bare wire to the tip, touch the solder to the wire (you will see it wick up), do same for other
strand of wire, then put both tinned wires together against the iron tip, the solder will flow together (takes less than a second),
pull both wires from iron making sure they stay connected allowing solder to cool (about a few seconds), wrap in electrical tape and then add the heat-shrink to the joint. Your done! Been doing it this way for quite awhile and aint had a failure yet. Like I said, soldering is easy once you get the hang of it.

Dave...