Stack it so that there is air space around the wood. Some old timers say to stack it lose enough for a rat to run through the woodpile. I cover mine with a sheet of tin roofing material and then weight it down with several pieces of wood to keep it from blowing away. This allows lots of air to get to it but does not keep moisture under it like a tarp or plastic would. I also stack it up off the ground on treated 2x4s or 2x6s, which once again allows air to move around it and keeps the ground moisture away from it.
Split wood will dry faster than whole logs and smaller pieces dry fastest. I know that may be stating the obvious but I thought I would go ahead and throw it out there.