Clean your planes of oily residue. Empty the tanks. Remove the glow plug from your engine and run a bunch of Marvel Mystery oil through it until you are certain that all the bearings are well lubed. Replace the glow plug and muffler, add some more Mystery Oil, and cap off the carb and muffler opening.

Try to store your planes somewhere that the temperature and humidity are relatively stable, especially if they are finished with dope. Keep your tramsmitters in the nice warm house. Charge all the batteries, and cycle them prior to the next seasons use.