What type of soldering iron did you use and what WATTS does it put out?
Higher wattage is better to a point . I use the Radio Shack higher end soldering gun, I believe it does max 220 or 250 Watts. Works very well and gets that solder heated up quick so you don't destroy stuff.
I think anything below 200 probably won't get the job done very well.
Avoid Radio Shacks 100W solder gun, it will go poof on you.