How to add unique meta tags, description and keywords to blogger

Since, my google Webmaster's Tool Diagnostics always tells me that I have duplicate Short Description and Duplicate Meta Tags. I've search for solutions that will eliminate this problem. What I want is for every page of my blog there will be a unique title, keywords and description set. To achieve this I have the following code:

<b:if cond='data:blog.pageType == "index"'>
<title></title>
<META NAME='keywords' expr:content='data:blog.pageTitle'/>
<META NAME='description' expr:content='data:blog.title'/>
<b:else/>  
<title></title>

<b:if cond='data:blog.pageType == "comment"'>
<META NAME='keywords' expr:content='data:blog.pageName'/><!-- I want to do something here -->
<b:else/>
<META NAME='keywords' expr:content='data:blog.pageName'/>
</b:if>

<META NAME='description' expr:content='data:blog.pageName'/>
</b:if>

This code tells us to set the keywords, title and description to the page title or pagename (this must be unique). I know it's not yet in that level to be good in SEO but at least it will eliminate the Diagnostics error.

What I want to do next is to set the keywords to blog post labels, and to add a unique description to every comment.

[edit]
Regarding labels as keywords, I was working at the loop but can't print it out inside the head tag finally I saw this blog :

url: http://www.moretechtips.net/2009/03/blogger-seo-tip-use-post-labels-as-meta.html
title: Blogger SEO Tip: Use Post Labels as Meta Keywords

And finally, I was able to do what I want :-D.

[edit]
//copied codes:

<b:if cond='data:blog.pageType == "item"'>
   <b:section id='meta1' showaddelement='no'>
   <!-- widget must be a of Type = 'blog' to have posts data exposed, and must have a unique id -->
   <!-- Empty Includables(functions) to output nothing, You must keep them ): -->
   <b:widget id='Blog200' locked='no' type='Blog'>
      <b:includable id='nextprev'/>
      <b:includable id='backlinks' var='post'/>
      <b:includable id='post' var='post' />
      <b:includable id='status-message'/>
      <b:includable id='comment-form' var='post'/>
      <b:includable id='backlinkDeleteIcon' var='backlink'/>
      <b:includable id='postQuickEdit' var='post'/>
      <b:includable id='commentDeleteIcon' var='comment'/>
      <b:includable id='feedLinks'/>
      <b:includable id='feedLinksBody' var='links'/>
      <b:includable id='comments' var='post'/>
      <b:includable id='main' var='top'><!-- Main Function of Any widget comes with ID 'main' -->
         <!-- Loop Page Posts (only 1 in a post page )-->
         <b:loop values='data:posts' var='post'>
            <b:if cond='data:post.labels'>
               <!-- If the post has labels, make Meta keywords by looping lables -->
               <meta name="keywords" content="<b:loop values='data:post.labels' var='label'><data:label.name/><b:if cond='data:label.isLast != "true"'>,</b:if></b:loop>" />
            </b:if>
         </b:loop>
      </b:includable>
   </b:widget>
   </b:section>
</b:if>