There are many people who say they need very specific circumstances for them to write.
It has to be perfectly silent, or; it has to be just the right level of noisy, but no one can talk to you, or; you need to be hanging upside-down over a vat of boiling acid so you really feel like you have to write.
They're all good, bu which one is best for you?
For myself, I need music to really get the visions flowing, but sometimes music can be too emotive. When your soundtrack strays away from the mood you're trying to create (such as writing a love scene and then crazy action fight music comes on) that can be distracting. So a lot of times, I will just go for a walk, listen to my music, get the scene sort of situated right in my head, then come back and sit down with no music, close my eyes, and just type.
Here's one of my personal beliefs: the more obstacles between your brain and the page you can remove, the better. Sometimes that's outside noise, sometimes that's just looking at the actual words on your screen. Touch typing is not a skill everyone has, but when you can close your eyes and just let the words flow from your brain to your fingers without having that extra step of reading them as well, I find that it really goes much quicker, and you don't lost what's in your head as easily. You just have to trust yourself when you're deleting things :P
Studies about as to how to make you more creative and productive, but the fact is that not everything is going to work the same for everyone else. So rather than looking at tips and tricks and stuff, (this article notwithstanding), think of the times that you had in your own life that you got the best writing done. When was that day that you slammed out 4000 words in an afternoon, each of them great? What were the circumstances for that? The likely fact is that they probably are recreatable - there's probably not anything that you can't come back up with. Well, maybe some of you got really inspired after your first child was born or something, but fine that's not recreatable. You just have to find something else.
Another key is, once you've found your writing zone, to not allow other things to get you out of your creative zone. Even when there are distractions (a friend calls, your kid needs help, people arrive unexpected, etc) you need to keep your head in writing-land. Don't think about the words, but do think about how some of your characters would deal with whatever distraction just came to hand. Don't just do it yourself, actually learn something about your characters when you have to deal with real life. You might learn something you didn't know about them. Maybe because of this learning you'll be able to craft more meaningful characters with more realistic personalities.
Remember, everything in life is something you can put into your writing, so don't think of everything you're doing as separate from writing. Look at life as research, and take everything that happens to you as a lesson that will make your writing better than it would have been before.
Alright, it was a short one today, so I'm out, and keep writing!