Lifehacker has a great writing tip that I take for granted, but come to think of it, may not be obvious to everyone: When you’re in a groove, don’t interrupt your writing with research.
The groove is much too valuable for that. When the words are flowing effortlessly, ride it out as long as it lasts. It usually takes a while to find that groove, so just go with it. I usually won’t break a groove to edit, either. Just let the words flow. You’ll always be more productive that way.
When you can’t find a groove, no matter what you do, then you’ve found a good time to research, or edit, or both. And sometimes in the course of doing one or the other, you’ll stumble back into the groove. If you do, ride it. If I’m in a good groove, I’ve even been known to close my e-mail, take my phone off the hook, and do anything to prevent interruption, so I can get maximum productivity out of that groove.
I wrote a 200-page book in about six months, and that was while I had a regular 40-hour-a-week job. The only reason I was able to do that was because I wouldn’t interrupt a groove to do research or testing. I’d write the idea, leave notes for myself, then come back later during a slump, do my research and testing, and fill in the details.
There were a couple of times I hit a groove around 11 PM, and ended up writing until 1 AM. I paid for it the next morning, but it was worth it.
One trick: I don’t usually do the TK thing. I leave notes for myself in square brackets. The only time you use square brackets is when clarifying a quote, so placing [VERIFY] next to a guess or something I’m not willing to bet my reputation on makes it easy to come back and find those spots that need attention. It’s easy to find with search and replace, and it stands out pretty well when skimming the text.