+1 on good gloves. Get the toastiest waterproofest ones you can afford. Anything less will leave your fingers wanting to drop off when the big freeze hits.
Also a good windproof jacket is a sound investment. Doesn't have to be thick, you can layer up below it. Windproof = reasonably waterproof too, as they use a very close woven fabric.
I used legwarmers all winter last year, along with my usual summer shorts, and they did me fine.
Shoe covers keep the feet warm, and shoes dry and clean from all the muck you get on the roads in the winter months.
I use one of those nice fleecy neckwarmers, and when it's really cold I pull it up over my mouth and nose. Got one with a cord around the top, so you can pull it tight and your breath will go downwards & won't steam up your glasses.
Mudguards. Defo gotta use them.
Get all of that lot and you'll survive all winter. Skimp on any at your own peril....