"Tin" the wire by melting some solder on it first, and have some solder already on where it is going to attach using small amounts in both locations.
Then hold the wire in place and hold the soldering iron to the wire just long enough to melt the solder and you'll see the two parts of soldering (one on the wire and other on the location you are attaching it too) melt together, remove the iron and continue to hold the wire in place for a few more seconds as the solder cools down and solidifies the connection.
Don't the hold the solder in a spot for too long though as it could damage the components if they get too hot.
If I plug in the guitar right after i make a connection is it possible for the electricity running through to make my wires pop off?
One more question I am wiring a JS1, and I've taken both green wires from the bridge & neck pup and wired them together to the same spot on the tone pot is that okay?? Same with the ground wire from both can I wire both together in the same spot?
Rich couldn't be more right about that! But pay attention to moro too. A lot of people melt the solder with the iron and let it more or less fall on the wire. That will never produce an acceptable connection. You have to get both sides of the connection (the wire and the part you are soldering the wire to) hot enough (with the iron) to melt the solder. You want the part to melt the solder, not the iron. If you are doing it right, it won't take more than about 2-3 seconds per connection.
Exactly, 2-3 seconds, more and you start risking burning components. I'd bet 1 second of wet solder on a tab is sufficient to heat that tab to temp, but not a ground grouping to the center of a case, unless you're running 60-100w of heat.
Oh, one more bit of advice--keep the tip of the iron clean. Soak a sponge in water and keep it handy so you can wipe off the gunk (oxidation and rosin, I think?) that builds up. The tip should be shiny and coated with a thin layer of clean solder.
Another thing to remember is that if the metal you're soldering onto has oxidized, you'll need to sand off the oxidized layer so you get a good contact. This goes for the undersides of PCB boards, the cases of potentiometers, etc.
For a perfect solder joint all parts that will be soldered should be held together without any mechanical stress on the joint and absolutely steady.
Most joints will last even if you held the wire just with your fingers as steadily as you could, but there still is some risk that the joint will become "cold" after a time (sometimes years). If you can find a way to use a fixation then use it even if it's just tape. It also prevents you from burning your fingers - on the other hand, it's more tempting to heat forever and melt the components... And don't cool the hot joint by blowing air at it, it should cool down gently to prevent internal tensions that might ruin the joint later.