One more thing about having your solder iron on the pads for too long. If you get them too hot the pad will actually separate and lift up off the PC board, tearing the delicate copper trace, and the PC board will be useless.

Using a solder wick braid is a good thing to do every time you are trying to remove solder from the thru-hole and pad. This is because after you use the solder wick you have a clean hole and a clean pad with just a slight film of solder on it and you have a nice open workspace without any old solder in there. Old solder doesn't have solder flux anymore -it's burned off-and won't "flow" around the component or wire leads and leaves an icy-looking "cold" solder joint, a dull grey glob of solder that is weak and doesn't conduct electricity very well. By wicking it off, the new solder, which does have solder flux, will be shiny, smooth, quite strong and conductive. I've been soldering since the early 70's and solder wick is a good friend if you use it right. No need for staples or picks, either.