I was asked to write about How To Write When You Have No Time. I will list three tips and tricks in an easy form. I hope this is helpful!
1. Carry a notebook around with you everywhere. If you make it a habit to do this, you might be surprised how often, and in what strange places inspiration hits. Jot it down quickly, and when you have more time on your hands, type it up. The typing it up process usually fleshes out the idea, makes it better (and, if you are writing for NaNoWriMo, you get a higher word count!). Really though, take a notebook around with you. Every. Where. You. Go.
2. Keep your writing brain open at all times. Many-a-time in school or at work, we writers will turn off (or turn WAY down) our writers brain. We stop looking at things and thinking "How would this fit in my story?" or "I could definitely use a description like that." Those moments are important. Ofttimes it is in one of those moments that the perfect sub-plot is born, or even your main character finally gets that fear he/she's been needing. Then, with all these fresh ideas, put 'em into the handy-dandy aforementioned notebook.
3. Last but certainly not least, do not give up. No matter if you feel you have no time, I guarantee you can find five minutes to write. And if you've kept your writers brain open, and you notebook in hand, you can do. You having a rough day, and don't feel like writing? Push through it. You can do it, I promise you. I had to do that yesterday, and it made it past a huge milestone, and now I am raring to go. You've got this!