TL; DR The best way to concentrate while writing? You have to figure it out yourself. What works for me is sound and energy.
If you do not want interruptions, wear fuck off headphones.
I like quiet. I need to be in a space where I am not going to be interrupted. Door closed, ideally. Noise-cancelling headphones on. The big, over-ear ones? Yes, because that is the headphone equivalent of having your office door closed. Fuck off.
Active mind, active body, rest mind, rest body.
Standing or sitting? I need both. I am compulsive. I move around every 25 minutes.
Put a Pomodoro timer on. 25 minutes on, 5 minute break. Every couple of cycles you get a 10 or 15 minute break. Stick to the first 5 minute break. If you burn through two 25s and then get a 30 minute break, sometimes that is what works for you.
Music
The music happens to have different vibes. Everything has a good beat, upbeat. The start songs might be pump up songs that actually even get me dancing. Catchy, hitting, pop and hip hop beats. The lyrics just get you going. Right now I am listening to the freestyle Interior Crocodile Alligator.
The other type of song is like hypnotic beat. All instrumental versions of hip hop by Jay Z, Kanye West, others. The internet is full of them. Some of Kygo stuff works too. There is one vlogging music guy that is key as well.
Ambiance - Light
Fake light works better for me. Fewer distractions. You put me in front of a window, and I love it, and it looks great in photos, and it feels good, and I absolutely do not write. Standing desk facing the wall or a cubicle. A screen where I can adjust the height. A comfortable keyboard.
When I am in the room during the day, I close the door and pull the shades. We have fantastic cellulose shades that still let in some light.
At night, I have yellow light bulbs. The daylight lightbulbs are good for staving off seasonal affective disorder, my gym has them, and if I use them while writing at night I get manic and all my sleep patterns get wrecked.
Ambiance - Location
I like my room. I like it neat. I used to think that having a disorganized room was good because then I could get to everything. The truth is that I had no fucking clue how to keep a room organized, what it mean to have an organized room, and did not realize you have to give things up (a disorganized room) in order to gain things (fast entry into mental writing space, a space that feels good for you and others to be in).
I like cafes. Problem is the chairs and ergonomics suck.
I like my cubicle, if I can keep down distractions. I like a place where I can walk to a window and get sunlight, fresh air, maybe even a conversation with a real human being that I like. If not, I will text friends.
Pro tip: workout equipment
The latest addition are two adjustable dumbbells. They go from 10 - 50 lbs in 5 lbs increments. They sit behind my chair and during some breaks, you can feel that you are getting antsy. Too cerebral, need some phyiscal.
Pick up two dumbbells.
Clean and push press (2 presses), do that once on each side.
Full dumbbell squat, do that 5 times.
Pull, staggered leg row or other type of row, do that 5 times.
Still feeling antsy? 3 pull ups.
Still antsy? Do more.