You already use keyword searching. For instance, if you're using Google, and you need to find information about a coffee shop in your town, what words might you use to search?
Why would you use those words?
Here's what I'd put into the search bar: "Cleveland Coffee." Like your search, I've tried to get the most important concepts in: I want to find a store that sells coffee, not just any store, so I use the word coffee. I want one in my town, so I add the word Cleveland.
Whether through a search engine like Google, or through a library database, keywords help you find information.
Keywords are what you type into a database to find books and articles relevant to your topic. Taking a few minutes to think about and identify some keywords before starting your search will help you search more efficiently, which will save you time (and probably a little frustration).
Look at the following example, courtesy of UCONN. You will see a research question broken down into its most relevant concepts, which become your keywords. Then it's helpful to think of synonyms for those keywords, because research is often listed under different words than the ones you have decided to use.
Did you find a good article? Great! Do you need more? Welcome to the club. You can find additional articles like the one you found by looking at the article's record in the database. Different subjects will often have their own specific terms to describe something, so it's important to mine the article you have for additional keywords. Look at the article's record, note any specific Subjects or Selected Keywords. Almost all articles will supply these in their records.