Winter boat storage:Disconnect and remove electronics.
Grease battery terminals or remove the battery if the boat is not being used at all.
Grease all steering joints
Probably a good time to check steering cables (if cable steering used)
Make sure cover is secure and draining water rather than pooling on the cover.
Throttle lever: strip and grease internals (if not done on the engine service)
Engine:Flush engine or run every couple of weeks.
Remove plugs and introduce some 2 stroke into the cylinders or run every couple of weeks.
Grease all points on leg and internal ball joints (throttle, gear selector) (if not done on the service)
Wind the steering tube in rather than leaving it out to the elements.
The school of thought seems to be to keep internal tanks full rather than empty. Run the engine dry of fuel or run every couple of weeks.
Trailer:Jack axles off the ground and spin wheels occasionally
Grease winch
Grease roller spindles, brake cables and compensator joint (if exists)
Go really mad and grease internals of the brakes!
Anything visual that you re worried about rusting could be given a coat of Vaseline or wurth hhs 2000 or suchlike
Best thing to do of course is: GO FISHING DURING THE WINTER!