Here is a sponsored ad from Cricket Wireless on Facebook.  

The bright green color immediately grabs your attention.  The generous white space helps you to read the add quickly, without getting lost in the details.  They implemented the rule of thirds by including content in each third.  The repetition of the cell phones in the middle of the ad draws your attention and quickly communicates that they sell a variety of models.  The included text adequately identifies the price range and let’s you know there are other plans available.