Why not fly in winter? Cooler denser air with lower overall relative humidity and less people at the field- Nothing better!!!!!

But If you Must-
1- Remove all fuel from tank
2- Remove all fuel from engine and put a few drops of after-run oil in it
3- Charge batteries and disconnect if possible
4- Clean plane and radio (store in warm dry place)
5- Huddle around a warm fire and wait for spring..