Design of the optimal local skin flap to repair a specific facial defect requires an understanding of the geometry of the various flaps, local facial anatomy, and the biomechanics of skin and soft tissue. The creative integration of these variables is one of the most challenging areas of facial plastic surgery. This article discusses some general principles of flap design with emphasis on the importance of skin tension and its distribution in preventing complications and maximizing the use of local tissue in difficult reconstructive situations.