At work, I use a 120W iron normally set to 320C, and leaded 60/40 solder. Gets up to temperature and transfers heat to the workpiece quickly, and with the occasional tip-change the same iron works for everything from soldering shielding tape over everything, doing wiring looms, connectors and sticking stuff on PCBs. I'm hardly an expert (although I rarely fuck anything up so badly it can't be re-done), but the golden rules for me are:
- Plenty of flux
- Clean EVERYTHING with plenty of IPA before working on it
- Keep that tip tinned and shiny
- Use the brass brillo pad things instead of a wet sponge
Lead-free solder is horrible, nobody I work with likes it, and thankfully we're not required to use it due to an exemption. I'd NEVER use the stuff at home either. Just wash your hands after handling it and there's no real harm... although good luck finding it at Maplin these days!