Soldering USB contacts - what kind of solder tip and what temp?
I would use a fine tip, very thin.
Also some very thin solder.   The tip &amp; the solder should be about the size of those pads or less.  I would also set my soldering gun to about 700&deg;F ( &asymp; 370&deg;C) (Lead solder, not RoHS)

First touch the tip to the pad, then touch the solder.  This will leave a little blob of solder on the pad.  

Next using multi-strand wire of AWG26 or 28, I would remove about 3mm of insulation, and tin the wire with more solder.  Not a big blob here, just wet it.

Last, place the wire on the pad, then place the soldering tip on the wire.  Push down very lightly.  After a second or two, the solder blob will melt, the wire will move down.  Remove the soldering tip.  Hold the wire steady for about 3 second, and you're done  :)

I would then look at it REALLY CLOSE with a magnifying lens or some such, to see the quality of my work.  

Last - After I'd tested it, I would cover the entire area with hot melt glue, so I don't break the wires later or accidentally rip off the pads.