As I have tried to get some writing done this summer, I have often thought back to an essay I read nearly three years ago (via Daring Fireball) dealing with what the author, Paul Graham, called “the top idea in your mind.” He described it like this:
I realized recently that what one thinks about in the shower in the morning is more important than I’d thought. I knew it was a good time to have ideas. Now I’d go further: now I’d say it’s hard to do a really good job on anything you don’t think about in the shower.
Everyone who’s worked on difficult problems is probably familiar with the phenomenon of working hard to figure something out, failing, and then suddenly seeing the answer a bit later while doing something else. There’s a kind of thinking you do without trying to. I’m increasingly convinced this type of thinking is not merely helpful in solving hard problems, but necessary. The tricky part is, you can only control it indirectly. 
I think most people have one top idea in their mind at any given time. That’s the idea their thoughts will drift toward when they’re allowed to drift freely. And this idea will thus tend to get all the benefit of that type of thinking, while others are starved of it. Which means it’s a disaster to let the wrong idea become the top one in your mind.
In college I typically wrote papers at the last minute but I did not start them at the last minute. Instead, I would often spend a period of days in which a particular assignment was the top idea in my mind. Ideas about the paper or its organization might come to me during breakfast, in other classes, or, I suppose, in the shower. As these ideas came to me I would write them down somewhere and when the time came to actually sit down and write the paper I already had an idea of what I wanted to say.
There is a crucial difference in my own experiences writing papers as a college student and sitting down to write a paper having never thought about it. In discussions with students about writing I try to emphasize that this work takes very little effort but can make the writing process much easier. Essentially, thinking about a paper “counts” as working on the paper, even if no writing is being done. Far too many students seem to sit down and start writing without having grappled with the issues they plan to address or how they plan to organize their thoughts. The result is work that may have all of the parts that the assignment asks for, but lacks cohesion or depth.
Faculty members are not immune to these problems. One of the difficulties I have faced in writing during the academic year is related to the fact that teaching is almost always the top idea in my mind during these time periods. I still have a hard time transitioning from teaching to research. I have actually had a fairly productive summer in terms of writing, but this productivity has slowed considerably since I started teaching a summer course a few weeks ago. Once again, teaching is the top idea in my mind. Unfortunately, Graham’s solution isn’t much help to me (or others who work at institutions that prioritize teaching):
You can’t directly control where your thoughts drift. If you’re controlling them, they’re not drifting. But you can control them indirectly, by controlling what situations you let yourself get into. That has been the lesson for me: be careful what you let become critical to you. Try to get yourself into situations where the most urgent problems are ones you want to think about.
Interestingly, this idea explains why I have a hard time writing as well as why those at research institutions may have a hard time teaching. In each case, the top idea in our minds is the thing that is most important for our continued employment.