How my blog looks while people see it from search engine. See the following image:
The text inside the red rectangle is called meta description of the post. This describes about your post in brief (150 chars). People can see at first this piece of information about the post. So, it should very specific and very crucial in respect of Search Engine Optimization technique. Previously there was no official method of editing this piece of information. Google Search Engine itself would select the most important part of the post and treat that part as meta tag. But now, Blogger offered Meta tag insert option from Search Preference. Go to Settings of your Blog. Then Click Search Preference. Under Meta Tags column Enable Search Description Option. Its that simple. Now you can enter meta tag for every post you create. And also you can enter the same for the existing posts.