You don't need great pains to put the meta description and keywords in each post. This meta will change automatically according to the post title.
How to install an Automatic Meta Description and Keywords for Blogspot in each post
1. Log in to blogger
2. Go to design> Edit HTML
3. Find the code like this: <title><data:blog.pageTitle/></ title>
3. Remove it and replace the code with the code below
<b:if cond='data:blog.url == "http://Your blogspot dot com/"'>
<title> <data:blog.pageTitle/> </ title>
<meta name='description' content='Your homepage description'/> homepage
<meta name='keywords' content='Your homepage keywords'/> </ b: if>
<b:if cond='data:blog.pageType == "item"'>
<title> <data:blog.pageName/> - <data:blog.title/> </ title>
<meta expr:content='data:blog.pageName + ", " + data:blog.title + ", " + data:blog.pageName' name='Description'/>
<meta expr:content='data:blog.pageName + ", " + data:blog.title + ", " + data:blog.pageName' name='Keywords'/>
</b:if>
4. Save Changes