Keep your neck warm, as well as your head, layer up, make sure at least one outer layer is windproof. I find in the winter it's not the temperature, it's the wind chill that makes it uncomfortable. Get some thermals from your local supermarket and good thermal socks, keep your feet warm. Gloves are a personal thing but I use Showa 282 temres.
I clean front doors using cloths, rather than wfp, so there is no water to freeze. Learn how to clean a front door quickly using a cheap microfibre cloth rinsed in pure and a glass cloth (I use paragon fish scale ones).
Any customers that want to go 8 weekly over the winter, don't worry about it, get on with it. (I am 8 weekly anyway).
Any customers that even hint about you not being busy over winter, I just say "I'm totally busy all year round"! Make them feel the odd one out! (I actually am so this doesn't occur anymore).
You can even throw in..."the week before Christmas is my busiest week as many customers ask for an extra clean because the family are coming down" (this is actually true for me).
Remember that in the winter, the sun is very low, and this will highlight dirty windows.
Any customers that cancel over the winter...you know what to do!!!!!