Play the percentage game, keep away from hero shots especially where your opponent has just hit a bad one. If he hits OOB make sure yours is steadily on the fairway, if he is in the water make sure you lay up or hit long, when he putts see and learn how his ball rolls and make allowances for fast or slow greens. Leave your opponent to pressurise himself and as Bill said play the course nice and safe.

Oh! and never give up.