Flux can help alot as well. If the tip doesn't want to stay tinned, then dip it in some flux. Same goes for wire. If you have a wire thats being difficult and you can't tin it, then just dip the end of the wire in some flux and the solder will stick to it like no tomorrow.
Speaking of soldering, I just soldered this up last night.
Its the dome light for my car. These things will be brighter than the surface of the damn sun.
I still have to get some resistors for it, but other than that its done.