Prepare your palette by adding fresh paint, ideally to wells that have sloping sides. With a wet brush, make your mixtures of paints in the palette's mixing area. For convenience, add enough paint to complete what you plan to paint in the sitting.
Dip your brush into the paint and wipe off excess paint on the rim of your palette. The amount of paint on the brush will depend on how bold you want the paint as well as the size of the area to be painted. For a more transparent look, add more water.
Outline the shape of the picture you wish to create on the paper. When outlining, press down lightly with a brush that has little ink. Alternatively, you can sketch the shapes with a pencil prior to filling them in with watercolor.
Plan the source of light in your comic book to give direction to your shadows. Ink heavy-line weights on the dark sides of your characters and objects with your watercolor to establish the light source and give depth to your painting.
Paint in vivid facial expressions consistent with the comic book. Use a dry brush technique, which uses paint with little water and dry paper. The crisp lines highlight the main characters.
Feather your paint in order to soften a hard edge, add volume and form to items in the comic and show a light to dark graduation. The paint should appear to go from light to dark.
Paint the background of your comic book. Depending on how much detail you wish to show, you may use a lot of water to give soft and blurry edges or show bold detail with strong color. Use a variety of techniques such as splattering and sponging the paint.
Lift off areas that you do not wish to keep. With most types of watercolor paint, you can dissolve the paint by wetting the area and blotting it away. This can be useful in the case of mistakes or when you wish to highlight another area of the comic.