Last time, we got to the point of tracing out each moving part and numbering them. Trace one more copy of your original, onto more substantial paper. This will be your color scheme. If you haven't picked out your colors yet, this is your chance to make multiple copies and experiment. James Gurney, the author and illustrator of Dinotopia, has a lot of good advice about color schemes in his book Color and Light. A good rule of thumb is to stick to 3 or 4 colors per character, with one of those colors in contrast to the others.
Small to medium brushes are nice for this, and they should be fairly soft, but not really floppy like the brown or sable watercolor brushes. I like synthetic brushes because they last longer too. It's really important not to make your watercolors too wet. I usually use one or two brushfuls of water to wet my main paint color, and make a little puddle in the lid of my watercolor set. (My favorite brands are Prang and Guitar. Crayola is actually very good too. Avoid Roseart at all costs - they are pale and wimpy.) Don't use the straight paint color unless you want a really bright color, although that might be good for a superhero. I usually make Westerns and/or ghost stories, so I like muted colors. I always mix my paint in the lid, and I leave the mixed colors in there so I can rewet and mix them later. That way I don't have to use black to darken my colors, which I find muddies them. Browns and purples are better if you need to darken a color. There is also a watercolor called Paynes Gray that comes in squeezy tubes, and it's a very lovely alternative to black. That's the only expensive watercolor I buy. *
Here are my brushes and one of my messy paint lids, with some wet brown paint:
You can see how I mixed the old dried dark brown and dark blue paint into the new brown paint to get a more interesting color.
Do a light, flat layer of paint on your copied drawing. Keep a scrap piece of cardstock handy to test your colors on before putting them on your actual picture.
Once that's dry, add darker shades around the edges to give the figure some depth. Also, you can bring out details and textures. I blended the shading in more on his pants, since they are a rough wool, and I used a hard edge on his leather jacket and boots, since leather has some shine to it. To blend the shading, put a very small amount of plain water on the picture first, then carefully add your darker color. Use a thin line, since it will spread into the damp area, and you can always add more later. For the harder edge, simply paint a darker color over the dried paint. For the darker colors you can also just use less water for a thicker paint. The areas farthest to the back of the character will be the darkest (the wrapped around scarf, the underarms and flares on the jodhpurs)
Next: Cutting and gluing!
*Besides my squeezy tube of Paynes Gray, I have discovered that Prang's powdered tempera paints are absolutely gorgeous. They have a velvety texture and muted colors that I really like, but they are very hard to find. They are what I used on all the characters and backgrounds in Ghost Train.