Scientists quite often have to present their work graphically. This is common practice, e.g., at scientific conferences. This talk gives an introduction to poster design. We will cover the planning phase and the actual realization as well as explain in great detail a variety of issues such as generally accepted rules for content and layout, things that are well received by a target audience, color symbolism, the use of illustrations and graphics, recommended fonts and other rules for text formatting, and special requirements of the print medium as opposed to on-screen presentations. After the theoretical introduction to the topic, common mistakes in poster design are discussed, and numerous posters are viewed and analyzed by the course participants.