Howdy GHedrick!
For starters you'll want to change the lower unit oil and fog the cylinders. That way you're ready to roll in the spring.
To fog the cylinders you can usually spray fogging compound into the air intake while the motor is running. Do it a few times until the motor almost dies and then on the last shot spray enough fogging agent into the intake to totally kill the engine. With manufacturers recommend taking out the spark plugs, giving each cylinder a squirt of compound, and then turning over the engine to coat the cylinders. Either way works...but the first one is usually the easiest. You might check online to see what Merc recommends for a two stroke.
I also like to hit all the bolts on the inside and outside of the engine with Corrosion Block or something similar. Lastly I'll take off the prop and grease up the shaft splines to keep the prop from corroding onto the shaft over the winter.
All this stuff will pay off in the spring when you're ready to hit the water again. Good luck to ya