Here is a quick video I made showing basic soldering skills:
Some key points to consider:
1. use a quality soldering iron with adjustable temp control. If your temp is too low you might cook the internal parts of the potentiometer before you melt your solder.
2. get in, solder, and get out as quick as possible to minimize heat on delicate components.
3. score the area you are soldering with 80 or 120 grit sandpaper.
4. tin your wires and lugs, ALWAYS.