To write great copy, you must adhere to three principles:
• It must be relevant.
• It must be credible.
• It must be as short as possible (not just short).

Notice how the word “creative” is absent. People don’t have time for you to be cute, play tricks, or gimmick them. They want the facts, and they want what they’re looking for now….

Kill the jargon, fluff, and hype. Not everyone can be the number one, premier, most trusted, scalable, most robust, and leading vendor. But if you do make a claim, make sure you can validate it immediately. Customers are more sensitive than ever to shoddy sales pitches and false claims.

Speak to customers in an authentic, human voice. Embrace transparency and authenticity and, wherever possible, embrace the voice of the customer. While you’re at it, make sure your copy has a voice that matches your brand; a voice that people will remember.

Stop haggling over copy length; customers don’t care. They care about getting the information they need from your copy, quickly. Make sure you answer their questions and close the loopholes in as few words as possible…. [E]ditors who can slash copy to its meaty essentials are invaluable.

[Excerpted from Writing Better Copy for the Web 2.0 Landscape; emphasis added]