I'm coming to this thread late, so this may not be of much value. But here goes... When you write, write what you know, write from the heart and write uniquely. Do not spin articles, it's very clear when somebody does that. And as it's been suggested, write for your reader foremost. They will buy from and you show you love. I don't know if I agree with Craven on the 500 word limit. many article directories require at least that much and sometimes more. It's more important that you say what you have to say and say it well. If that takes 550 word, so be it, but if it takes 1100, that's fine too, so long as you're not repetitive and rambling. if you need to make a point make it. Don't get hung up on word count.
A good Article should be ORIGINAL Should be written in excellent grammar. Should be CopyScape Passed Intelligent Usage of Keywords (KWD ,Keyword Placement, LSI Keywords)
But don't you think there's a minimum word limit? I feel articles posted on blogs shouldn't be less than 450 words.
Add value and facts and make it user friendly. don't bother about search engine, just write for humans. Don't try to be different, try to be unique with your approach. don't write for the marketing purpose, write it for knowledge sharing. And, do share your article before publishing with your friends to get their views Hope this helps
not more than 500 words sounds good to me. the only problem I have is that for SEO these days it appears more than 700 is required, on top of adding 300 on other content on the page, links etc.