[UPDATE April 27, 2015: Blogger now support labels which helps to categorize posts within a single blog, but it is still very useful for me to maintain multiple blogs so that I may target each one for very different audiences. Within each blog, I am using labels to help further categorize the posts.]
Blogger doesn't have a feature to set up categories within a blog, but does allow for multiple blogs under one profile.
So I created two new blogs: MBA Notes from a Santa Clara University Alumni and LinkedIn Notes. After setting up the blogs, I realized that I like having multiple blogs better than just one blog with categories. I used basically the same template for each blog, but made subtle customized differences.
For example, in my personal blog, my profile is near the top of the right side of the page, which is the default. This is useful because people coming to this blog may be looking for information about me, and would like to see my profile. For the other blogs, readers may be less interested in seeing my profile, and more interested in seeing links to recent postings. So I moved the chunk of template code for my profile below the recent posts and archives box. Also, by placing the recent posts and archive links closer to the top of the page, search engines might give more weight to the relevant keywords in those links.
Other customizations I've made include pasting in code for an invisible counter courtesy of StatCounter, RSS feeds thanks to Feedburner, Google searches and advertisements from Google's AdSense program.
I've read a little bit about blogrolls and will consider that as a future add-on to one or more of my blogs. Another add-on, HaloScans's trackback system, doesn't seem too appealing based on what Dave Taylor and "Improbulus" say on their blogs.
Does anyone have any other add-ons to recommend?
I don't know how to code in CSS from scratch, but having had my fingers in so many programming languages and knowing HTML, it's not too hard to figure out how to do some basic customization with the Blogger template. Those who are not experienced with programming languages may have a tougher time customizing Blogger templates.