If you've dabbled in SEO, you've probably written a meta description. A meta description is the text shown immediately below the title of the website on the search engine results page (SERP). It is the highlighted portion shown in the image below.
Google will use the meta description you provide as long as it is relevant to the content within the page. (If not, they'll use an excerpt from the page.) One trick you can use to write effective descriptions is to treat them like a text message. Messages sent from a mobile phone must be less than 160 characters, so right away that tells you to be brief. Pretend you can only send one text to your friend to tell them why they should visit the page you are describing. This will help you include only the most essential information. Remember, with a meta description, you are not trying to explain the entire page. You are not even trying to give an overview. You are trying to get someone to click on the link. That being said, it's OK to create a little mystery. Pique their curiosity!
For inspiration, look to Google Ads just to the right of the organic results. Often these text ads are much more effective at entices people to click the link. Getting on the first page of Google won't maximize your efforts if you have a low click through rate (CTR). When you treat your descriptions like text messages, you'll be more likely to get clicks, and more clicks equals more conversions!