Here is how I lay out my posters on a 4' x 8' sheet. 

The yellow and green on the right show the way the sheets would be cut. 

The artwork on the left illustrates the basic poster design, though this year, some design elements will be different from the example below. 

Here is approximately what the poster designs will look like. Note the numbers that correspond to the sheet layout. For example, Sheet #2 will be printed 3 times.