A friend recently commented that he is "allergic" to routines and schedules. I love the freedom of the free-lance life, but I also recognize that sometimes having no set routine is dangerous. A routine or schedule often also helps the person who has another job and lots of other demands on his or her time. These tend to crowd out writing, which is very frustrating.
One solution is to allocate certain days and times for specific writing-related tasks. Here is an example (of course you can modify it any way you need to):
Monday: write query letters to agents, publishers, producers. (If you have little time, you might set the goal of writing only one).
Tuesday: brainstorm current project--this could mean figuring out the storyline, or planning interviews, or whatever is relevant to what you're writing.
Wednesday/Thursday/Friday: writing. Set a goal of one page or more per day.
Saturday/Sunday: one day off, the other for writing or editing.
You can do this with as little as a fifteen-minute chunk per day. Schedule it and take it seriously. Some people say, "I can't write in tiny chunks of time." You can learn to do it--mostly by just doing it and not being critical of the results. Treat it as a learning experience, and have faith that over time you will develop the concentration to do it better and better.