Get the smallest soldering iron you can.

Click to expand...

I would offer quite different advice. To get this particular connector to solder properly requires a fairly robust iron. Small, low-wattage types will struggle to get the pins hot enough to solder well.

Click to expand...

I think Mars478 was actually referring to the size of the tip, not the iron itself (even though he said iron). Like tomlee59 said, a powerful soldering iron is best. I recommend a temperature controlled station, with a fume extractor, brass tip cleaner, and lead tin 63/37 solder with rosin core and 2% flux. Don't use lead-free solder, it is weaker and difficult to work with. In the long-term, you may find a temperature controlled station will eventually pay for itself as you do more soldering jobs.