Heat, more heat and then a little more for good measue. You have to have a clean iron that is tinned with a bit of solder on it so you make a good heat contact when you put it on the wire or post. . You have to have clean wire. Dip the end of the wire in some paste flux and then scoup off a piece of solder onto the tip if the iron and hit the wire with it. The solder should flow onto the wire in less than two seconds. All of this has been said before by many posters on this thread. Clean and hot with the right flux and solder and soldering is easy You have to have all four, three of the for is trouble.

Don