Here are some different approaches to time from Zen Habits. Writers have an interesting relationship with time. I’m happiest when it disappears and things are clicking on the page. I already tend to work by the week. Rather than scheduling a certain number of hours to work, I tend to set word or page goals. They haven’t been working for me lately, so I lighten up, get some rest, and go to look at great paintings to get going again. I do like his point about having a theme for the month. If you get stuck, it’s one strategy to keep going.