Wow, a lot of great info about materials. So I guess I'll concentrate on technique.
My first model was a Barbarian that I won from a "name that monster" contest at a Game Keeper. (It was a beholder)
He turned out really really well, possibly because I had a lot of experience painting props and sets. (Drama Geek... That's me.)
I didn't use most of the techniques I list below, mostly because I didn't know about them. Instead, I got light and shadow by using my darkest shade as the primer then drybrushing the base and the highlights...
It turned out very well, better then I thought it would, but he has a ... somehow... very stylized look to him... As opposed to most of my minis now, which are more... Organic.
I think.
Anyway... On to my advice about actually painting a mini.
Stages of painting...
Prime: Completely coat the mini with one base color of paint. Keep in mind that, even though this coat gets covered, it will affect the final outcome of the mini. A white primer turns out a very bright and "upbeat" looking figure. Black tends to give a "darker" feel. A green base will make the figure look vaguely "sickly". Somewhere, I have three identical minis, painted identically, except for the base coat... I'll see if I can find them and post a picture later. Experiment with different color primers. (Spray primers are good, but you usually only find them in white, grey, and black.)
Base: Paint parts of the mini the color you want them to be. Paint the fleshy parts flesh, paint the clothing, weapons, armor, and what-have-you whatever colors you want them to be.
Highlight (aka-Drybrush): Take the colors you used for the bases, lighten them with white. Dip your brush in this lighter shade, then tap it on a paper towel, or whatever, to get most of the paint off. Lightly brush the mini so the raised places get just a trace if the highlight.
"Ink": Take the colors you used for the bases, darken them up a bit. Usually with black, but try using other colors as well. Then add a good amount of water to the paint so that it's, well, like ink. Gently brush the ink onto the mini. As the water evaporates, the paint will concentrate into the deeper parts of the mini, giving a great sense of depth.
Seal: Games Workshop sells a good, matte, spray seal. This helps keep the paint from chipping or rubbing off. This step is totally optional, but it helps keep your minis nice. I have also used spray seal that is sold at art stores for "fixing" pastels and charcoal to good effect... However, even though it looks matte on paper, it tends to be rather glossy on minis... This can ruin the affect you've been working so hard for.
It really doesn't take that much more effort to paint like this... And sometimes, I look at one of my minis and it doesn't really look to me like I've done this... But boy oh boy... Can I tell when these steps HAVEN'T been done.
More later...