As well as being dark, you will also have noticed that winter is generally cold and wet.
Staying warm is something I have never really got right, so you may want to factor that in as you read this post: although I am ideally placed to tell you a lot of things which don’t work very well.
The first thing I have to recommend you avoid is cycling with a backpack on. I used to do this when I was a student, and it generally meant that I arrived with a very cold front and a very warm back. At the time I was working part-time in the IT department and I used to go and stand between the windows servers and the aircon unit in the machine room to reverse that effect. It’s probably not practical to have everyone doing that, so avoid it if you can. I don’t carry cargo these days, but if I did I would use a rack and panniers.
In terms of clothing, designers are starting to acknowledge that you need to be warmer at the front than at the back. I bought some Altura tights a few weeks ago which are made with WindTex as the front leg panel and normal lycra for the back and sides. The more wintry ones have WindTex round the back and sides and the even-warmer Super Roubaix fabric at the front. I haven’t cycled on a cold enough day to really test whether these work yet.
For the top half, of course, I have a couple of stylish OpenCycleTeam jackets. Comment below if you fancy one 
. I think the WindTex version cost about £60 each.
I’ve been more successful at keeping dry, particularly now there are decent mudguards for road bikes. The main problem which isn’t solved by mudguards is wet feet; which I’m told can be partly addressed with overshoes, although I remain unconvinced of the theory. The last time my feet got soaked, it was the tops of my socks which got soaked first: the water got into my shoes by wicking down the sock. Maybe I should just try overshoes and test the reality.
As well as yourself, you need to concern yourself with how your bike will handle the wet. The main thing you should do is make sure that you use a ‘wet’ rather than a ‘dry’ lubricant on your chain. Bike shops in my area like to recommend dry lubricants to all and sundry, presumably on the assumption that their customers will be fair-weather cyclists. I don’t like dry lubes at the best of times, because if you follow the instructions you need to re-apply them every 50km, although they are very good for short rides in dry and dusty conditions. I’m using Finish Line Ceramic at the moment; it seems to do the job.
What are your favourite ways to keep yourself warm and dry in the winter?
I have some overshoes, and would confirm Phil’s theory. They’re really no good when it’s very wet. However, one big plus is that in frosty and other cold weather, they keep the chilly wind out of your ventilated cycling shoes and feet stay much warmer.
[...] you to being soaked, and once there, the rest of the journey home is only going to get warmer. As Phil discussed earlier, on a night like this, nothing is going to stop your feet getting wet and in some ways less [...]