add meta tags,keywords for a specific posts on blogger

1. Switch to the Edit HTML tab of your template and find this line:

b:include data='blog' name='all-head-content'/

2. Add this code just below that line:

<b:if cond='data:blog.url == "http://YOUR-BLOG-URL.com/"'>
<meta content='DESCRIPTION' name='description'/>
<meta content='KEYWORDS' name='keywords'/>
</b:if>

This was done to add META Tags to the main page of the blog.

3. Now add this code just below the code you add just now:

<b:if cond='data:blog.url == "http://YOUR-BLOG-URL.com/2009/03/xxx.html"'>
<meta content='Type you post description here.' name='description'/>
<meta content='Type, the, post, keywords, here' name='keywords'/>
</b:if>

Replace http://YOUR-BLOG-URL.com/2009/03/xxx.html with the
URL of the specific post you want to change the META Tags of.

4. Repeat Step 3 for as many blog posts you want to have unique META Tags for.