Give her a good clean and polish first, make sure oil is topped up (it might be best to do an oil change so its fresh oil in the engine as oil old will contain elements which over time can eat away at the inside of your engine), spray with a little WD40 to protect the surfaces (excluding the brake discs!) from any dampness during the winter.
Add a fuel stabiliser to the tank of fuel, making sure the tank is as full as possible. Run the bike for about 10-15 minutes to make sure the stabiliser is all the way through your fuel system then top the tank up to the brim.
Try to get the bike off the ground on paddock stands, if you can, so you don’t get flat spots in the tyres, failing that move her round the garage in the winter so that different areas of the tyres are in contact with the ground.
You may want to stuff a rag in the exhaust (and the air intakes if you have them) mice and such have been known to set up home in them during the winter months.
Take the battery off and keep it inside on a battery tender (cold will kill a battery). If you are storing your bike for the whole winter it’s best not to top the battery up by running the bike for a while every week as the sudden heating and cooling of the bike can cause condensation to form inside the engine, which will cause damage.
Cover her up and hope the winter passes fast so you can get back out on her quickly.
Me? I ride all winter! Today was lovely, although cold, and I really enjoyed riding round. If you ride through the winter there are other considerations such as how to deal with potential salt damage, but I shall cover them in another entry.