As Gypsum experts we always like to provide information regarding Gypsum board installations. They require careful planning: accurate measuring, cutting and fitting are very important. In residential buildings with ceiling heights under 8′1″, wallboard is best installed at right angles (perpendicular) to framing members as this orientation of the panels leaves fewer joints to finish. On long walls, horizontally attaching boards of the maximum practical length will minimize the number of butt joints. Avoid using damaged board.

Information source: http://www.gypsum.org/