Someone asked me to expand upon what it means to be an independent librarian. In my case, I take on private contracts to perform research for companies and individuals. Most of my research is done in cultural institutions and courthouses around the state. I use the internet to confirm that resources are in particular locations, and then travel to the site to use and consult the primary sources. In some cases, I use digital collections, but for the most part, my clients want me to consult the actual items. Some independent or free-lance librarians / researchers search for information about companies and products. That type of research is usually called "corporate intelligence". I don't know how many of this variety of researcher is still out there. They were pretty rare in the early 1990s when I started my research business.
Where do I get clients? Well, I do some subtle advertising and then I have my website. Most of my clients come from referrals from other clients and librarians. I've been doing this a long time, so I have lots of happy clients. It's a fascinating way to use my degree and keeps me fresh. What I love most about being "independent" is that I get to use libraries and archives. I have a really good idea of what researchers need, which institutions have the best materials, and how to ask questions. I can interact with all types of librarians and archivists and learn more than I ever imagined.
Here's where I put theory into practice. I use research materials. I think about how they work and are arranged. Then I teach about the tools to my students. In the meantime, I'm probably reading about the tools and the documents so I understand how the agencies and organizations collected the information, why they wanted it, and what they did with it. Then I can apply that historical context to the documents and think about how I can use them or teach them to my students.
I apply my library research skills to my work every day. There's never a dull moment.