1.Login to your blogger dashboard--> layout- -> Edit HTML
2.Click on "Expand Widget Templates"
3.Scroll down to where you see <p><data:post.body/></p> .
4.Copy below code and paste it just after the <p><data:post.body/></p> .
<script src="http://ajax.googleapis.com/ajax/libs/jquery/1.3.2/jquery.min.js" type="text/javascript"></script>
<script src="http://blogger-related-posts.googlecode.com/files/related-posts-widget-1.0.js" type="text/javascript"></script>
<script type="text/javascript">relatedPostsWidget({'containerSelector':'div.post-body','loadingText':'loading...'});</script>
5.Click on "Save Templates" and now you are done.It will look like this.
