1. Stop being precious. No, it is not the case that you can only write if you have 3 full hours, perfect silence, a 110 degree latte, and Mercury is in retrograde. Sit the fuck down and type.
2. You do not have writer's block. That is not a thing. Writer's block= "I can't muster the will to write." Write something-- it doesn't have to be your current project, or the scene you need to write. Write a book or restaurant review, a character sketch, anything.
3. Write an outline. I'm firmly against the "seat-of-your-pants" method of writing a book. Yeah yeah, everyone has their own process, but if your process is writing 85,000 words before you realize there's massive plot holes, I would argue that your process sucks. An outline is effectively a to-do list. I have a full-time career in an unrelated field--I do not have time to dawdle in front of the computer wondering what to write. I have a list I have to get through. Which leads me to...
4. Write out of order. I feel odd saying it because I thought everyone did, but I have met some people who feel like they can only write in order. That they must work on Chapter 3 before they can work on Chapter 4. Write whatever strikes your fancy and fill in the gaps later.
5. Utilize "yaddah- yaddah". Say you're breezing along. At the end of this scene there needs to be a pretty cut-and-dry convo-- like "Why didn't you go to the police when you found the dead body?" Maybe you know the answer or maybe you don't, but right now you don't care. Just write "blah blah" or [they have the convo about the police]. Go back to it later.
6. Establish healthy boundaries with respect to research. Either do A or B. A is research something moderately to thoroughly before you write anything about it in your book. B is make shit up. What you don't want to do is be happily chugging along, then come to the part that takes place at the (real) Mayflower Hotel in DC, then spend two hours straight learning everything about it, including what type of mortar was used to hold the bricks together when it was being constructed. Either do it before or just make it up--just make it good whether the facts are real or fake. There's such a thing as doing too much research. For example, this strange place, the McMillan Sand Filtration Site, is the location of a set piece in the novel I'm revising right now. I already knew what it looked like from having driven by it. I knew what it was basically, and spent about 5 minutes doing research to find out when it was built, when it was operational, and when it stopped being operational. Did I need to know the architect or how exactly the water was filtered? No. If the story was actually about the Site itself, maybe, but there was a level of "need to know." If you can't go to the Mayflower and you don't know what the staircase looks like there, you can either spend a bunch of time trying to find out, or you could make it up, or just say "staircase"--and the more important thing would be to have one or two details about something else that feel real even if they aren't. You're writing fiction, not history. (um, unless you write nonfiction.)
7. Don't write what you know, write what you love. Stuff you find fun will always come faster. The harrowing tale of your own personal trauma--that's not going to come out quickly. But think of your guilty pleasures. The tropes you love in both "good" and "bad" TV, movies, and books.
8. Don't show your stuff to people, including yourself. You need to be able to produce material even without the threat of a deadline imposed by a critique partner. You need to be free from voices which doubt your direction. (I am pro-beta reader, but increasingly skeptical about workshopping as a need as opposed to a form of socializing, and I'm not sure about critique partners while you are still drafting.) Don't go back and revise your writing--or at least no more than a page or two.
9. Block off time when you are specifically not allowed to write. I once heard something about psychologist Viktor Frankl. He had a patient who worried constantly. He told them, I'm assigning you to worry as much as possible between 9 and 10 am. Lo and behold, the person did their assignment so well that they were actually sort of burnt out on worrying after that. This is the obverse of that. In thinking about your work day, don't look for time to write--block of time when you are specifically not allowed to write. For weekend days, don't let your calendar show a gaping open space all day that just says "write book." I wake up early and go to work--so no potential free time until 4:30, 5. I have a dog to take care of, my own maw to feed, and I have a specific time where I like to get to the gym. I write between dinner and the gym--I stop at the predesignated time, no matter how hot things have gotten. If I have what appears to be an empty weekend day, I block time off for things other than writing--weightlifting, leisurely walk with my assistant editor (dog), chores from 1-2:30, 2:30-3 panicking about the increasing meaninglessness in the world, reading 5 to 6, social event from 6 to 10 pm. Which means I only "get" that bit of afternoon time to write. When you have a bunch of stuff going on, you don't have the luxury of time. You have to be efficient because you have no other choice. You are assigned to write then, and no where else. You don't have to stay home from a social event because you are (tragically) working on your novel--you'll just write faster and harder the day before and the day after. Time is a commodity. If you have too much time to write, time has no value. You won't get anything done.
10. Think about your ideal reader. Don't think about publication. Or agents. If you will offend someone. About Comic Book Guy tweeting about how you got some detail wrong. Your ideal reader is a lot like you. She's excited about your characters and story. Your idea writer is not your mother. Or your judgy aunt. Or Snarky McSnarkface from your MFA. This book is for you and no one else right now. The only notes to hit are the ones you want.
In honor of NaNoRiMo-- which I'm not doing, I'm going to try to blog once a day for the rest of the month. In particular, I'd like to focus on the "I'm not a full time writer" thing and how you can still make it work. That said, I might just end up writing long blog posts that are actually just hypercritical reviews of Assassin's Creed starring Michael Fassbender.