I think the most important thing is to have fun and enjoy what you're working on. From your conversions I can see you're already there, so keep it up! There is some really top notch work on this site (and plenty of it). Great for inspiration, just don't get discouraged. As long as you're having fun painting, sculpting, converting, that's all that matters.
As for acronyms, probably the most common one you'll see around here is NMM (non-metal metallics... non metallic paint made to look like metal, like you mentioned). There's also TMM (true metal metallics... using metallic paint).
I think for most of the regular sized figures here people are using brushes. For things like vehicles and the giant models, some use airbrushes and some use regular brushes. Airbrushing can be a lot quicker for those large projects, but it has it's own learning curve.
For the shaky hand, I like to rest my wrist against something while I paint. Could be the edge of the table or something sitting on top of the table (box, specially made painting arm rest, whatever). I've also seen people use two hands to paint. They hold the brush as normal and then press their index finger against the brush near the tip. They only do this for the real fine detail work, eyes, etc. and of course you have to have something else hold the figure. Just some ideas to work with.
In regards to basic painting, a wet palette is very useful! You can make one yourself pretty easily. An internet search should turn up a variety of tutorials on how to do it. But all you really need is a shallow container (I use a small piece of tupperware, a sponge to hold the water, and paper. The kind of paper is important. I use paper designed for wet palettes... but you don't have to. I think I've heard of people using butcher paper. Again, an internet search should give you some ideas. To get better results and smoother shading try thinning down your paints. Most tutorials mention getting them down to the consistency of milk. You just want them to be semi transparent. For your base coat this means you'll have to pile on 2 or 3 layers to get complete coverage, but the end result should be a very smooth even color. Then, when you use lighter or darker colors to shade and highlight, the semi transparency will help with your blending.
Hope that helps!
