Write anywhere. Any time. Any how. Just write.
Sometimes easier said than done, though, which I know better than most. Here are a few sites that have helped me, inspired me, or simply made me feel less alone.
You can't get published without submitting your work. (Unfortunate, but true!) This site makes it easy to keep tabs on where and when you send out your writing. I've been amazingly organized since I started using it. Plus, it provides a great way to research publications, publishers and agents. Highly recommended.