Can't agree more. As the days get shorter and the sky gets gloomy, my mood becomes gloomier. I've been aware of this for several years now. I noticed that when I was in college that I skipped more classes during winter and had the worst grades during winter quarter.
Some of the things that work for me to keep myself motivated- Exercise, waking up and repeating to myself- "what do I need to achieve today?", eating healthy, turning the heater off sometimes and keep the house as bright as possible.
Networking is key and a lot of times students forget to leverage off of their current networks. Networking doesn't necessarily have to be connecting with new people but getting referrals from friends and family can be huge. I've noticed in my experiences that a lot of times students don't know how to ask someone to help them find a job.