Another way is to use a pantograph. This is a device that uses to concept of levers to recreate a drawing on a larger scale. I have tried both the method listed above and the pantograph, and my experience has been the pantograph is trickier to set up, but in the long run, it is easier to use and saves time. Incidentally, by adjusting the levers, a pantograph can also be used to turn a poster-sized masterpiece into a tiny illustration.