1. Never use a metaphor, simile, or other figure of speech which you are used to seeing in print.
2. Never use a long word where a short one will do.
3. If it is possible to cut a word out, always cut it out.
4. Never use the passive where you can use the active.
5. Never use a foreign phrase, a scientific word, or a jargon word if you can think of an everyday English equivalent.
6. Break any of these rules sooner than say anything outright barbarous.
The source for the rules is Orwell's essay Politics and the English Language. To find out what these rules of writing have to do with politics, read the essay and see what you think! Especially if you have read Orwell's amazing novel 1984, you will really appreciate the essay's conclusion:
Political language -- and with variations this is true of all political parties, from Conservatives to Anarchists -- is designed to make lies sound truthful and murder respectable, and to give an appearance of solidity to pure wind. One cannot change this all in a moment, but one can at least change one's own habits, and from time to time one can even, if one jeers loudly enough, send some worn-out and useless phrase -- some jackboot, Achilles' heel, hotbed, melting pot, acid test, veritable inferno, or other lump of verbal refuse -- into the dustbin, where it belongs.To get a sense of what Orwell means by the language of truthful lies and respectable murder, see the Wikipedia articles about Doublethink and Newspeak, the totalitarian language of thought control in 1984.
For Orwell, the way we use language is far more than a question of style.
(web source: Wikipedia)