When I'm staring at an open fairway and looking to hit a long drive to set up a good birdie opportunity, I make one simple change to my address position to help me find a few extra yards. By widening my stance slightly (stepping back with my right foot only so I don't change the ball's position in my stance), I create a stable base from which I can make a more powerful, athletic swing.
Take a step back with your right foot so you can maintain balance during a more powerful swing.