disconnect hoses from washdown pumps,livewell pumps. and pump them dry.
don't leave electronics to freeze.
put the batteries in the basement. they'll stay warm. just charge them in the spring.
soak the ba-jesus out of the engine with wd40, everywhear.same for bilge wiring/fuse pannels, etc...
get a vent in the shrink wrap so moisture don't accumulate.
treat cushions with armor all or something.
treat canvass-plastic.
no cans of soda left behind, very messy, trust me
