A good excerpt from an artnet article - Learning on the Job - by Jerry Saltz. Found the link on the MAN ArtJournal blog.
To me, theory and positions are important, but they often lead to dogmatic thinking, obscure writing and rigid taste. Knowing where you're coming from means knowing what you like before you like it and hating what you hate before you hate it. This takes all the life out of art. Theory is about understanding. Art is about experience. Theory is neat. Art is not. My only position is to let the reader in on my feelings; try to write in straightforward, jargon-free language; not oversimplify or dumb down my responses; aim to have an idea, a judgment or a description in every sentence; not take too much for granted; explain how artists might be original or derivative and how they use techniques and materials; observe whether they're developing or standing still; provide context; and make judgments that hopefully amount to something more than just my opinion. To do this requires more than a position or a theory. It requires something else. This something else is what art, and criticism, are all about.