Layer up and DO get yourself a good balaclava that covers down onto your chest as well.
Actually I use two balaclavas on the coldest days. I did find that this causes my helmet pads to expand to deal with two "socks" over my head - but for $12 I bought HJC replacements helmet pads to bring the helmet snug again for summer riding. One set for winter, one for wram weather.
Supposedly my FirstGear armored mesh jacket is not suitable for winter - but I don't have an armored leather jacket so I just use several layers to stay warm under the mesh.
A windscreen would probably help me stay warm ....but I don't like them so have no plans to install one.
I keep the face shield cracked just a bit to keep from fogging - and my eyes get used to the cold in time!
Rain pants over my Slider jeans....and boots with a couple socks.
I can't go across the state, but I can ride for an hour or two on my days off, and to and fro to work if the roads are clear....The tricky bit is the stupid weatherman's forecast can catch me out while at work. A couple of times I had to ride home as it was snowing. The City Grips helped some. (that's when I start thinking 'side-car', but no....)
My fuel injected LIKE fires like a maniac on the coldest days - and its nice being air-cooled so no worries about stuff leaking or freezing. I let it warm up while I finish my coffee and work on the gloves.
It was 1 degree one morning for my ride - but the bank downtown said it was 3 - so my record is fuzzy.
You wouldn't want to miss a day like this just because it was in the teens.
More than once I stupidly got my fingers cold with the gloves off to take a picture! Spent time hugging the exhaust and belt cover - but once they're cold you gotta go home.
The Europeans probably have heated grips, gloves and vests when they head up into the Alps.
Lucky rascals.
Stig