How do I write a good ad in Google AdWords?

 You write a good ad in Google AdWords by creating a headline that captures attention and includes the keywords, description lines that accurately describe and emotionally amplify your product features and benefits, a straightforward and assertive call to action, and a display URL that is simple, easy to read, and is usually your top-level domain.

You need to be able to write a good ad in Google AdWords in order to attract clicks on your ad. Good ad copywriting can take years to lean. You can, however, learn to write solid ad copy in Google AdWords by following some basic rules.

Your headline in Google AdWords should first and foremost contain the keywords being searched. If you’re selling consulting services for Google AdWords and all your keywords contain “AdWords,” you’ll definitely want to include “AdWords” in your headline along with emotionally amplifying modifiers. “Superior AdWords Experts,” “Experienced AdWords Pros,” and “AdWords Secrets Exposed,” for example.

Your two description lines should accurately describe and emotionally amplify your product or service. The more clear and accurate your description, the better you qualify your audience before they click your link. Since you pay per click, you want your audience to know exactly what you’re offering so they don’t waste their time and your money. “Get expert help for your Google ads,” “Start making money now with AdWords,” and “Learn the secrets of AdWords Now.”

You should include a clear and concise call to action in the second line of your description. “Buy now,” “Sign up today,” and “Call for a free quote,” for example.

Your display URL should be simple and easy to read and your destination URL, or landing page, should be the most relevant page on your domain for the product or service you’re advertising, in order to achieve the highest conversion rates.

To learn more about the important techniques for writing effective ads in Google AdWords, read Don't Waste Money on Google AdWords.

See: http://www.ppcanswers.info/2010/07/how-do-i-write-good-ad-in-google.html