All about meta tags: Must implement in a Blog

How to add Separate Meta Tags for Individual Posts in Blogger: assess answer at http://bloggerstop.net/2008/11/how-to-add-separate-meta-tags-for_25.html
Avoiding duplicate meta tag penalty by using if condition
http://bloggerstop.net/2009/04/duplicate-meta-description-and-titles.html
or
http://cranked.me/2008/11/duplicate-title-tags-meta-descriptions.html
Also check out
http://anshuldudeja.blogspot.com/2009/08/remove-duplicate-content-and-urls-from.html