There is no way to force Google to display your meta description in the results pages. Google will use your meta description if it feels it's more relevant to the search results than other text it could have grabbed from the page. To encourage Google to use your meta description, be sure that it includes words that people searching for your site would use.
For example, if you have a solo site and your model name is "Sexy Sally", you would want to include "Sexy Sally" in your meta description:
Here's an article that goes into further detail about this.