Don't think of your desk as a flat surface: adjust placement of reference material to be easily visible without neck or eye strain.

Books, papers, and other reference materials that you consult in the course of your work should also be arranged in such a way as to minimize eye and neck strain. Group items close to one another that you use at the same time, such that materials you use while looking at your monitor are beside your monitor, and so that information you might need while talking on the telephone is near to the telephone. Also consider placing materials at different heights, so that you have a “bird's eye view” of your information. There are different stands and monitor clips that can be used to fit your needs.