I'm going to share a dozen tips for writing that have been useful for me in getting my four (nearly five) books written in the last twenty months ... take them for what they're worth. I would argue (although not very hard, but that's just my way) that they're all worth a try, but you should certainly feel free to discard whatever doesn't work for you.
Contrary to what I thought when I began writing, I don't need monastic quiet in order to get words from my brain to the page ... I actually got some great writing done (a couple of times) in the middle of a busy/noisy/crowded ski lodge this winter. If other conditions are favorable, I can work around all manner of ambient noise ... in fact, a totally lack of other noise can be a distraction in itself.
Sometimes the blank page (or computer screen) leers up at me, and defeats me before I start. I get psyched out by the pressure of writing 1,500 or 2,500 words, and the solution is simple ... don't. I make a deal with myself to write a scene, an encounter, or a conversation between my characters. With the pressure off, I often find that I can keep the writing going after I meet the mini-goal, and if not, then I take advantage of one of the other tricks further down this list.
A comfortable table and chair to write from is very important to me, and it should be to you as well. If the setup makes you sore or wiggly, you will not be able to share your best efforts with your readers. With the right table and chair combination, I will sometimes write for hours without noting the passage of time.
In a perfect world, I would always be able to write with natural morning light gently/indirectly filtered through trees from behind me, but I'll settle for no blinding glare or flashing distractors in my field of vision. It's often possible to change the lighting by moving your workspace by a few feet or simply rotating it slightly.
I like to get mildly hyped on coffee when I'm writing, and keep riding the caffeine-train as long as I can maintain the proper level (not enough to get jittery, not so little that I nap under the table). I also keep a glass of water at hand so that I don't dehydrate.
I write best when there's music playing in the background that is soothing and interesting and without singing. My favorite is mellow Mozart, although when I'm working through tricky sequences/sections, I sometimes switch over to Bach's Goldberg Variations.
I write better, and longer, on an empty stomach ... or at least not a full one. I will generally eat some breakfast, let it settle, and then begin to work without eating until I'm done writing for the day. The smells and textures distract me. I also find that I subconsciously worry about gumming up my keyboard, and am over-careful. Those, in combination with the simple fact that eating uses at least one of my hands, work together to derail my creativity more than the food benefits me.
Having dogs is useful to me as a writer in a number of ways: they listen to my ideas without judging, a walk every once in a while is a great way (for all of us) to stretch and breathe, and watching them act/react/interact with themselves and the world around them is always interesting.
I keep a pad and pen handy for when ideas or questions occur to me, knowing that having written it down, I can forget it and get back to what I was working on. I also use the paper to map/outline characters or segments of stories.
It may sound silly, but I bribe myself with promised rewards for work completed ... an episode of "Archer" or bowl of ice-cream or something fun to read on my kindle is a great (semi-intrinsic) motivation to keep working. Having a treat to look forward to helps me get the words out of my brain and into my laptop.
I pardon myself (in advance) for writing crappy material every time I sit down to write. I never count on the first draft of anything being great, but sometimes I have to get from point 'D' to point 'F', and can feel that writing segment 'E' is going to be messy; I have learned to live with it, knowing that I'll be able to clean things up in the re-write; give yourself the same permission.
If I'm in a jam, and the words aren't coming, I'll often take a ten minute reading break with one of my teacher-authors (Lawrence Block, Stephen King, Elmore Leonard, or whoever's writing I happen to be in love with at the moment). I use their writing as both break and tutorial, and more often than not can climb back out of the slump that I was in.
These tips aren't foolproof, but they generally help me get some writing done, even on those days when I think/feel that I'd prefer not to, or start out feeling as though I can't. I hope that one or more of them are of some use to you.