This is, obviously, easier said than done, but keep the four basic elements of an ad in mind (clarity, simplicity, impulse to action and intrusiveness), and follow these basic guidelines from advertising copywriters:

  1. Use an active voice, not a passive voice.
  2. Use energetic verbs and phrases, not dull or tepid ones.
  3. Be specific, not general or abstract.
  4. Use "you"--speak to the customer. You're explaining a desirable benefit to another human being.
  5. Make your ad no longer than it has to be. And how long is that? As long as it takes to communicate your key benefit to your customer.
  6. Keep headlines short.

Excerpted from Knock-Out Marketing: Powerful Strategies to Punch Up Your Sales