Whether you encounter electron powder diffraction patterns everyday, or run across them only rarely, interpreting them may require a bit of preparation. But it's easy to lose track of the numbers for your microscope's camera constant, not to mention the bewildering array of lattice parameters and symmetries that one may encounter in the microscope. In that context, we describe overlays you might want to assemble for measuring camera constants, and for recognizing crystal systems most likely to yield electron powder diffraction patterns in your lab. Pulling this out of a drawer and/or computer folder thereafter might help you come up with quick answers, even if you haven't thought about analyzing diffraction data for quite a while.