1. Write a new post.
2. Copy given code below and add ur part of article u want 2 Highlight in given place in between code.

< div style="width:200px;height:300px;border-top: 2px solid #000;border-bottom: 2px solid #000;border-right: 2px solid #000;border-left: 2px solid #000;"> Ur Text Here</div>
More info -> http://tips-tricks-for-blogger.blogspot.com/2009/10/highlights-blogger-article.html