Before you get started, you have to choose your brushes and paints. Hopefully you already have brushes, if not, your foray into art just got very expensive. Never buy inexpensive brushes in a kit unless you're planning to use them to apply liquid masking. They're good for that, but not much else because they shed hairs and the entire brush head can come off. Good quality artist's brushes can get pricey, but they're worth it. A single brush can cost over $20, so keep your eyes open for half-price sales, craft store coupons and clearance sales. Don't be afraid to buy synthetic brushes. I have some very nice synthetic brushes that work beautifully. Avoid sponge brushes like the plague and make sure you buy brush cleaner soap or you'll be washing the color out of your brushes for an hour after you're done painting.
Paint: Watercolors come in liquid, tubes, cakes, and raw pigment, or you can use colored inks. The only one I don't recommend is the cakes. Just stay away from them. You'll never get good color quality out of them and rubbing your brushes across a hard cake wrecks the bristles. Liquid watercolors have excellent color quality, but I've found they have a tendency to bleed. Raw pigment can be mixed with either linseed oil to create an oil based paint or dissolved in water to make watercolors. Ink has excellent color fastness, is long lasting and water-soluble with vibrant color and true transparency.
Transfer the sketch to your watercolor paper. I use carbon paper to do this. Use a good quality paper and don't over saturate it or the paper may curl or buckle and the colors will bleed together. Layering one transparent color over another will give you a different color, so don't overlap and leave a few minutes in between colors to let the first one dry to avoid bleed. I always start with the central figure. Here I started with the lighter colors in the wings, skin and clothing then added darker color in layers until I had the effect I wanted. Just remember that you can't lighten it after the fact. Details, such as shadows and features, are added after the base color is laid down.
Background: Apply background color (like the water and the tree) very carefully unless you are using masking liquid to block color transfer in places you've already painted. I never use masking liquid. I prefer to work around those areas. It takes as much effort to fill in the piece you're masking out as working around and the masking liquid ruins the brush you use to apply it. Make sure your already painted areas are completely dry then use a round brush with a pointed tip to apply clear water around those areas. The water will only go where you apply it so don't be afraid to try it this way. Once the paper is wet, apply the color to that area. Work quickly, but carefully, to fill in the area. You can also tilt the paper and let the color flow over the wet areas for a more natural effect. For the water, I started with yellow and built up the greens, bunt umber and sepia in different areas and let them run together. Then I used gouache at the edges and thinned opaques to give it a murky effect. The lichen covering the tree is also gouache, but the highlights on the catkins are a mix of transparent burnt umber and opaque white watercolor tube paint.
And that's the finished painting titled "The Spicebush Fairy." I've been painting watercolors for years and I love them. They're quick and they can be a lot of fun. I hope you won't be afraid to give them a try and develop your own technique.