Metal Brillo pads in every orifice, tail pipe, air filter openings, vent holes from foot wells to plenum chamber. yada, yada, mothballs on glass ash trays everywhere else. Add dryer sheets with mothballs if you like.
Cover the cowl air intake and close the big door under the dash.
Check under the hood and over in the fender cavities regularly for varmint signs. Ditto the cavities on the sides of the trunk and under the spare tire.
Check the cabin and the trunk regularly too, looking for signs of the varmints. Obviously, clean out the nests as soon as you see them.
Also, remove everything from the trunk and store the car with it empty, but with moth balls.
If it is a roadster store the car with the top up.
Disconnect the battery ground circuit and sprinkle baking soda all over the batteries and the trays.
Add Stabil to a half empty gas tank and then fill it up to FULL. Run the engine for five minutes or more after adding the Stabil to get it through the entire system
If there is any chance that you think that moisture may be an issue during storage pull the floor mats and any trunk lining and let the metal surfaces breath.
The rest is standard procedure. Lots of oil in the cylinders with a hand turn over, plugs out, every thirty days. Fresh oil and filter too. If you can't remember when it was last done, do a hydraulic system flush and bleed, brakes and clutch. Air up the tires to 35 or 40 PSI. If you can, set the car on shop stands and let the suspension/tires dangle. Plugs back in by three hand turns.
Grease job, including the parking brake cable. Lube all hinges and locks with appropriate lubricant.
Wash, air dry thoroughly and a wax job before covering with a BREATHABLE car cover.
Note taped to the inside of the windshield describing what has been done. This helps the next guy if you get run over by a bus and the wife sells the thing just to get it out of her sight.
The best thing is to NOT store the beast. Just keep on driving it in all except the worst weather or salt on the road.
Jack