Wax on, Wax off
Do you ever let your surfboard pile up amongst other surfboards? If so, you probably have a mess of wax on the bottom of your board. Although this may seem harmless, it can actually slow you down. Remember your surfboard is a planing surface and like airplane wings, it is designed to let a substance (water vs. air) move against the surface at rapid speeds. In the case of a surfboard, it's called hydrodynamics but the principles are very similar to aerodynamics. Airplane manufacturers will shave off the bumps and screws down to a smooth finish for better aerodynamics. The same concept should be applied to your surfboard. Scrape the wax off the bottom of your surfboard and make sure there is nothing protruding to slow you down. The smoother your surfboard, the more fluid it will move through the water.