I got some vitreous enamels last week for a certain piece I have had in the back of my mind for several years. I got the little sample kit from Rio Grande and a couple bigger jars. I have never done any enameled pieces, except for test pieces in grad school, which was a requirement for a class I was taking. Since I have never really done any enameling I also got the book The Art of Enameling: Techniques, Projects, Inspiration by Linda Darty. It seems to be a good book so far. I bought it on Amazon without having looked through it, I almost didn't get it because it has projects, but there's not much space devoted to them.
So far I am just doing test pieces. I like the rough granular texture from underfired enamel, what the enameling book calls sugar fired. That is my main interest in enameling. I am just as interested in the textures as I am the colors.