This chapter includes recommendations regarding the aerodynamic design of tandem wing aircraft. First, when tandem wings may be beneficial (and when it is better to consider the conventional scheme, or canard, or flying wing). Then, how to choose the overall layout and dimensions of the tandem wing aircraft as the design process differs greatly from the one for a classical aircraft. Next, principal suggestions are listed if there is a need to (1) increase maximum lift-drag ratio (and therefore flight range), (2) increase maximum lift coefficient (decrease the stalling speed), (3) shift the center of gravity range backward/forward, (4) expand a range of the center of gravity, (5) increase rolling stability, (6) increase directional (yawing) stability. The second edition of the book was updated on new studies that were reflected in the recommendations.