Ooh, pendants! Soldering is fun to play with -- I do it quite a bit. One thing to remember is that you definitely get better with practice, as in anything.
When you are doing any soldering you will need the following:
-whatever you want to solder (in my case, that is usually glass)
-copper foil tape (This is something you adhere to whatever you want to solder -- this is the only way that solder will actually stay on what you are working with. Otherwise it will either burn, shatter your object, or just generally not stick and make a mess.)
-flux (this is a chemical that you need to use in order to make the solder flow and stick to your foil correctly. If you don't use flux, your solder might stay on, but it will look pretty crappy and will be really difficult to put on. You will need to get a little brush and just brush a bit onto the area you want to solder. If you use too little, the solder won't flow well. If you use too much, it gets messy.)
-lead free solder (you'll want to use this if you are making something that you actually want to wear near your skin. Lead solder is more for something like a suncatcher or window, etc.)
I personally use a soldering iron that has a temperature control on it. You will want the temp to be almost on high, but maybe a notch or two lower. Like shewolf said, you will want a wet sponge that you can use to sort of wipe off any excess solder that may build up on the iron when it is hot.
Once you have the piece ready and copper foil put on (be sure to make sure this is down smooth and even -- you can use a bone folder or something along those lines to really press it onto your surface you are working with), dab a little flux onto one side and hold your solder in one hand, soldering iron in the other. (When I hold the solder, I keep it on the plastic roll it comes on and just hold onto the plastic part -- even though it's not melted yet, it can still conduct heat if you are too close to the heat source!) Then slowly follow the solder along with your iron, trying to keep a steady movement and speed. You want to end up with a nice, smooth soldering line. (ideally, not patchy)
After you are done soldering, let the piece cool for a bit, then wash it off with dish soap and water. (that's what I use anyway) You can use an old tooth brush or a sponge to clean -- you want to make sure you get all the flux off. (there is also a chemical called flux remover out there, but I have never tried it.) Dry it off and polish as you want. Try not to use anything with ammonia in it for cleaning though, it can tarnish the piece.
Phew, that was long winded! I hope that helps!