Aspen Comics And Top Cow colorist Jasen Smith has posted this handy image that helps breakdown the different styles of coloring. Now it's been many years since I did any comic coloring, but to break this down even further… the Flat-Style is also the basic first step in most of these. Flatting the image, like in the bottom right panel, is the process of simply coloring the image with mid-tones. Then you go in and render with highlights and shadows. You can do that with a couple different options if you are doing it digitally, using a darker and lighter color would be the basic airbrush style while using dodge and burn tools can work as well but is less exact. The Lasso brush is where you segment off the area you want to get better control. I've never done the cell shaded technique, which makes me think of more Manga-style comics.
This is a nice guide, though I think there are probably a few more variations than that. But if you are trying to convey what you are looking for to a colorist, this chart is a good place to start.
If you are interested in comic book coloring, a good place to start is Hi-Fi Color who have a nice how-to section along with offer up some really good books on the process.