Forgot a few things.
Get a waterproof motorcycle cover at least, it's better than nothing.
Lube everything, and put dialectric grease on all electrical connections.
Be sure you're controls are as watertight as you can get them. Frozen cables suck.
Battery tender is also a good idea, as is lower weight oil.
It's funny, you get double the attention riding in the winter.
People seem to be amazed at seeing a vintage bike flying down the road when it 23F. (-2C) out.