A classic fan pattern is shown here like a clock.  Cast out at 10, then 11, and so on until you get to 3, parallel with the shore, then return counter-clockwise on the half hours: 2:30, 1:30, 12:30, and so on.  If I'm in an area where I've had success before, I'll repeat the pattern with shorter casts, but if it's an unknown spot I'll move on after a dozen casts.