Know what it is you are trig to say, and make sure you can describe what you want to say in a single sentence. If you can’t then change your idea.
Establish a clear structure to your article, your reader should be led strongly by the hand through your article, not left wandering around wondering where the piece is going.
The Tone you choose is vital. Anger, condescension, general whining or being a smart arse won’t help.
Choice of language e.g If you are selling high tech products make sure the language used suits, an informal approach will be bad for your image.