Larger figures are a lot more complicated than small ones. For one thing, there's a bunch of pieces involved. This is the Pit Fiend just how he came out of the box: no head, wings or tail attached. The fire ball is also a separate piece:

I decided to paint him assembled. With some figs, you have to paint them in sections - sometimes you can't paint an area if it's completely glued together first, but I was lucky with this guy. Here he is glued together:

All the flash and rough casting lines have been filed down. Because of the amount of gluing, I needed to fill in the gaps with putty. We use modelling putty - it's really smelly. I push it into the crevices then smooth it out with my fingers, then sand it when it dries. Here's the back of the head, the wing joins and the tail seam:
My least favourite part: primering. I always use white primer so that I can see all the details property before I start putting paint on.
The first paint is applied! Pit Fiends are primarily red, but we already have two really red ones that L did. I started with a burgundy wash base and bright yellow for the wing membranes, teeth/eyes and fireball.
A shot of the back. There are a couple of layers of orange on over top of the yellow here.
Progress: several more layers of red and orange added to the burgundy base, and more layers of successively darker orange on the wings, toning to red.
And in a long session, he's finished! Top brush coats of dark orange, ivory on the teeth and claws. The base was painted, then I glued a black hobby sand to it.
Some extra ivory was added to the creases on the wings to make them stand out more. It's also been fully black-lines to emphasize the muscles and to add definition and depth.
A close up of the arms and the fireball. You can also see his eyes - I gave him slit pupils.
A close-up of the head. He's a nasty piece of business.
Grrr!
This is the stuff we use. We both have little bottles (shown) that we put a bit into so that it doesn't dry up on us (dollar store is a good place for mini bottles), and I use a palette (also dollar store) for mixing up my paint, water and floor polish. You use up a lot less paint this way, so it's a good method for preserving some of those really old paints.
This is my least favourite stage. I hate blocking all the colours in - it takes a long time, it's finicky (although easy to fix up later), and I usually don't have a clear idea of what I want the figure to look like.

The shield was glued on last because I had to paint all the stuff under it (his arm, the leather straps and a couple of pouches). The final touch: matte finish spray to protect him and he's ready for battle.
This was one of the first pieces I did using floor polish. Yes, floor polish. We add it to the paint (plus a bit of water) on a palette before applying it to the fig. It thins the paint down but suspends the colour evenly, whereas with just water, the pigment tends to settle which results in an uneven wash. 
These are our paints. They are a mix of Testors model paints, Partha Paints, Citadel Colour (Games Workshop) and Reaper Miniatures. Some of them are pretty old - we keep them from drying up by just using the colour from the lids and adding water when needed to thin them out a bit. There aren't many places in town to buy paints anymore, so we try to conserve what we've got.
Equipment
New Figure
This will be a Pit Fiend with a ball of fire in his right hand. That's his head and the ball of fire on a piece of metal on right. My next job here is to sand all the pieces down, glue him all together, fill any cracks with putty and then primer him. He's going to be a big job, but will look great when he's done. The big pieces like this tend to make people ooh and ah, but the small figs are actually harder to do.