Also, store it with the piston at BDC to keep the compression longer. Just spin the flywheel when the glow plug is out until the piston is at the bottom of the sleeve, then put your plug back in (or else you'll end up submitting a post in the "Latest Screw-Ups" thread when you take your rig out to run it and forget you have no glow plug in it!)
Not that it's ever happened to me, of course! :ahem: