tips on soldering
In addition to the other comments - if you're soldering to something that can sink a lot of heat (a great big copper connector, or the ground plane on a circuit board), you will probably need a fairly broad tip. A finer tip can't transfer heat fast enough, so you end up having to hold it in contact for far too long to get hot enough to melt the solder and (counterintuitively) you end up melting plastic or overheating components. Doubly so if you've cranked up the heat to help.
I've been trying to ride my bike into work instead of driving lately, but today it decided it's had enough of hauling my fat arse around and the derailleur hanger snapped in half.
Probably should use it as an excuse to upgrade, but I hate shopping for expensive things.