So, how do you unleash a click-through-compelling meta description?
Be Descriptive. The language in your meta description should introduce the user to what the page is about. In general terms, sketch out the page’s content. If the user is going to the trouble of clicking on it, he or she wants to make sure that the page really is about what they are interested in.
Be Persuasive. Great meta descriptions involve a touch of the persuasive. To get clicks, go ahead and tug a little bit. Some SEOs advocate using a call-to-action in the description. I’m not convinced that this is necessary; I do, however, recommend that you create a meta description that invites a response, even if it doesn’t directly call for it.
Inspire Curiosity. One of the most persuasive things you can do with your meta is to spark curiosity. This is particularly true for informational queries (as opposed to transactional queries). By the time a user finishes reading your description, they should be curious about what the page will say about the topic. You need to provide just enough information to explain what the page is about but not so much that it ruins the curiosity factor.
Use The Right Words. The keywords may not matter for search engines, but they do matter for users. In order to be compelled to click, the user needs to see relevant words. These words should be associated with his or her query. The right words in the right places make the difference between a SERP entry that gets overlooked, and a SERP entry that gets a click.
Make Them The Correct Length. If you write a meta description that is too long, Google will truncate it. The standard accepted length is 159 characters long.