[MetalMan]

I seem to have a different technique than most of you guys. Instead of tinning everything first, I first slip the wire into the plug. Then I clamp the plug in my vice, and touch the iron to the exposed wire/end of plug. I put some solder on to allow better heat transfer, and as each strand heats up, I add more and more solder. In the end, I get strong joints that have yet to fail me (and I've done 30+ 4mm connectors).

I do it this way because I couldn't imagine slipping 12ga. wire into a 4mm plug with solder on it already.