Temperature of the soldering iron should be about 150 degrees Celcius above the melting temperature of the solder, so with a regular 60/40 solder 350 degrees celsius is good. As was said earlier, clean the tip on a dry or moist rag, apply a little solder to the tip to make a heat bridge and heat both the pad and the wire/pin. Then apply some more solder on the pad and wire/pin on the opposite side of the soldering iron. Remove the solder and remove the iron. This normally takes only a few seconds. Heat it too much/long and the pad will loosen... If the solder balls up, let the solder cool down properly, add some flux and reheat for a few seconds.

Stig