Never look at a reference book while doing a first draft. You want to write a story? Fine. Put away your dictionary, your encyclopedias, your World Almanac, and your thesaurus. […] O.K., so here is your choice: either look it up in the dictionary, thereby making sure you have it right – and breaking your train of thought and the writer’s trance in the bargain – or just spell it phonetically and correct it later. Why not? Did you think it was going to go somewhere? […] You can check it … but later. When you sit down to write, write. Don’t do anything else except go to the bathroom, and only do that if it absolutely cannot be put off.

–Stephen King

{from the inspirational ‘Advice to Writers’ site}