The number one thing to do in my opinion is, make absolutely sure there is no water in the lower unit. I have made it a habit of draining and refilling the lower unit in the fall. At least that way I know there will be no water in the unit plus,, It will be ready for spring.
I see your from AL. so I'm not sure if you would have a freeze problem or not, but leaving water in the lower unit will certainly rust bearings and gears.
I like to add Sta-Bil to the gas and then run the motor.
Drain the carbs,, and I like to fog the motor. That's not really necessary, if it's not going to set an extremely long time, but I still do it.
Pull the drain plug, tilt the boat as to drain out any water and cover the boat up. I like to leave ventilation to keep my boat from becoming musty.
Then I pack the wheel bearings and lube the trailer. I'm all set for spring.