Measure, plan and cut pieces of drywall. You will want to hang pieces from top to bottom and have the fewest number of seams possible. Be sure when you cut to err on the side of caution by cutting the pieces longer rather than shorter. You can file a long piece down with a rasp, but you will not be able to add drywall to the end.
Measure and plan pieces to fit around fixtures.
Hang drywall pieces from the top pieces to the bottom, butting the pieces against each other. Attach the pieces using drywall screws. You should screw the center of the board first. Then, secure the edges. Be sure not to put a screw less than a half inch from the edge. Keep screws flush with the board, and try not to screw them in so deeply that they tear the paper on the drywall.
Apply a small amount of compound, and then apply additional compound or mud along the seams.
Apply your choice of finish to the wall.