1. Do not write long sentences. A sentence should not have more than ten or twelve words.Click through for the rest. I agree with all of this as an exercise, but think that literature would be poorer if these rules were absolute (though #4 is iron-clad).
2. Each sentence should make a clear statement. It should add to the statement that went before. A good paragraph is a series of clear, linked statements.
3. Do not use big words. If your computer tells you that your average word is more than five letters long, there is something wrong. The use of small words compels you to think about what you are writing. Even difficult ideas can be broken down into small words.
4. Never use words whose meaning you are not sure of. If you break this rule you should look for other work.
I write books. My latest is a YA science fiction novel called Homeland (it's the sequel to Little Brother). More books: Rapture of the Nerds (a novel, with Charlie Stross); With a Little Help (short stories); and The Great Big Beautiful Tomorrow (novella and nonfic). I speak all over the place and I tweet and tumble, too.