I recently wrote about tips to stay safe while running in the dark. On a similar note, I came across this list of 9 tips for your night runs. With the days getting shorter it is something that is relevant for most runners.
The article mentions that it takes true dedication to go running when it is already dark out after a day of work. Currently, my running schedule has me running after work four days a week and I sometime find it difficult to force myself to get out for a run after work when it is dark, especially if it is particularly cold out or raining. I think what keeps me motivated to get out there is the knowledge that it is my only option unless I want to start getting up at the crack of dawn again and the motivation problem goes away as soon as I start my run.
I also try to keep myself visible by wearing bright colours, with reflective patches if possible and as previously mentioned I use these turtle lights for lighting (they can be set to flashing).
The article also recommends not listening to music which is probably a good idea in terms of preventing an injury or accident. I used to always listen to music but since I have stopped I enjoy the fact that I am more aware of my surroundings while I run, regardless of whether it is dark out or not.