I do what I call "sampling" on a regular basis. This can be done any time for a brief period of time, and it is profitable to you.
Look through a book or Web site you are interested in, or some notes you have taken, and find a good illustration or bit of information. Then write it out in your own words, in a form you can plug into an appropriate piece later.
Be sure to keep track of these. It keeps you writing, even when you don't have a lot of time, and provides you a ready source to augment future articles. I do this a lot!