We are visual creatures. 30% of the brain is devoted to processing visual signals. So, it stands to reason that we need a space with visual signals conducive to writing and creativity. In other words...
...it's an excuse for a total room makeover...or two...or three!
There are certain things that seem to work.
1: You want a clean workspace. Clutter does not good books make. It's perfectly fine to be an angsty author (or pretend to be an angsty author) while you're writing--throw balls of paper all over and chuck pencils into the ceiling--but it should be clean when you start every day.
2: Limit the amount of time you have to leave the condcuive space. Yes, this is that excuse you've been looking for to buy a mini-fridge for your office. Definitely keep reference materials and notes as close at hand as is humanly possible. This include baby name books, dictionaries, thesauri, and other research things you got your hands on. It also means, if you can, keep the internet close, keep foods and drink close, and keep your friends and family as far away as humanly possible, if not further. I promise that, without fail, as soon as you get on a roll with your writing, they're all going to need you, do if you can put distance between them and your office, it buys you some time before they can get to you.
3: Cut distractions. Yes, you want the internet close--but only for research! Research, I'm afraid, rarely involves Facebook (not never, but rarely). Unlike most people, I don't reccomend complete isolation from the phone, however--but you should stick to your guns if your friends want to hang out or what have you. Say no unless you really need that break--and then keep your writing with you anyway--inspiration can strike in the oddest of places.
4: Surround yourself with writing. If you have, say, a map, tack it to the wall...and put your ouline beside it...surrounded by your character sketches and weapon schematics...which are across from the giant banner that says "You can fix it!" and kitty corner to the "Hang in there" poster. Anything to keep you immersed in the project.
5: Have a woobie. Or two. Or three. Or four. Have a woobie army, if you must. A woobie is just a general term fro something soft to use for comfort. Personally, I think lazy, fluffy cats make the best woobies, but if a cat isn't available, use a blanket, a dog, a stuffed animal, or a rather fuzzy (and quiet!) man.
6: Make it private. Whatever it takes. I write in my bedroom quite often and, as such, have an official "Do Not Enter" sign on it...gotten through less than honest means by my sister so many years ago. We need that privacy--sometimes the stress gets too much and, should anyone make the mistake of coming into the office, they may not leave with all of their limbs. Forewarn people and keep it cordoned off. If a door isn't available, use a thick blanket and just nail it up there--whatever it takes. Not only will it save the family, but it makes it sort of a developmental cocoon--you go in with nothing but a seed of an idea and leave with a brilliant (if slightly deformed) butterfly.
7: Make it yours. Many writers have children, and they love them, but it behooves you to train them that "When mommy's in her office, the Devil possesses her and she might kill you." You need to be able to do what you want in there. If that means you have to stage a mock battle with the dresser as a stand-in for your opponent, or put up pictures of mostly unclad people to inspire that brilliant erotica (why didn't I think of that before?), you not only should, you must--and you must have the space that allows you to do such thing without judgment or ridicule from anyone but yourself.
Of course, this is just my opinion--it works for me, maybe not erfectly for you--but it can't hurt to try, right?