Almost everyone who use Blogger like to modify their blog to enhance its looks or to increase SEO. It can be done by adding simple or already-provided widgets, or by modifying html template for more advanced bloggers.
Blogger might be not like self-hosted CMS that is more flexible to tweaked, but that doesn't mean you can't do something about it. There are tons of tutorials on the internet that can walk you through tweaking blogger. On this post, I would like to compile list of hacks, tips, and tricks that need to be known by any bloggers.
*This is a stub article. I will keep adding new contents to complete the list. You are welcome to make suggestions on the comments.*
Label Widget (Category)
Blogger: How to Change Post Display Format to "Post Title - Blog Title" In Google Search Result
The default format of Blogger site's page title is "Blog Title: Post Title", this is not good for your blog's SEO. If your blog title is long, people can't read your post title at all. Thus, make them less likely to click your site link on search result page. The tutorial on above link will optimize your blog SEO by swapping the position of post title and blog title on the page title to become "Post Title | Blog Title".
Related Posts Widget
Related posts widget in list format, without thumbnails.
A Simple Related Posts Widget For Blogger