I added a garage addition to my main garage, and they spend the winter in there where it is never less than 50 degrees. Once they salt the roads, i'm done.
Fresh oil change along with a fuel stabilizer. Keep a battery tender on it as well.
I start mine and warm it up a couple times a month just to lube all the seals.
Fill up tank, park in corner of garage, add sta-bil, plug tender in and let it sit. Sometime I cover bike and forgitaboutit so when I uncover in spring its like the first day I brought it home...
I have become a S&S rider..... Sunny and seventy before bike comes out of garage..
Jeff & dbmg have got you covered on this. A fuel stabilizer and battery tender are of utmost importance. Fresh oil is a good idea as well so the corrosive acids that build up in the oil are not just sitting in the engine during the downtime.
I do as posted above. I have a storage room down at my shop that it stays in, right next to the back office and on the way to the lunch room. So I get to stop by it for a visit, let it know how close soring is comming or roll it in the shop and tinker on it.