Most of the databases that you use to look for articles will use Boolean searching, so it's important for you to understand how it works and how the operators function. Interfaces differ between databases, but Boolean searching always works the same way. If you aren't familiar with Boolean searching and you only have 30 seconds, this is the video to watch.
Databases usually default to the basic search. It's important to know how to use it for a quick search, but I suggest using the advanced search feature for research.
The advanced search feature will be your best friend in your MLIS program and in your day-to-day work if you become a librarian. It allows you to refine your search with filters and other options.
You should also learn how to search using truncation and wildcards.
Truncation allows you to search for terms with various endings.For example, searching libr* would pull up results for library, libraries, librarian, librarians, etc.
Wildcards let you search for terms with unknown characters or multiple spellings. For example, searching wom?n would pull up results for woman and women.
The symbols used for wildcards and truncation vary from database to database, but the Help section of each database will let you know which symbols to use.
Most people are familiar with keyword searching. Keyword searching is what we use when we search Google or use the default settings of most databases. Keyword searching is a great place to start and can help you get an idea of what is available, but it does have disadvantages. When you do a keyword search, the entire record for an item is searched, so you will get irrelevant results in your search (e.g., if you are interested in finding out about storm damage and libraries and you search "libraries" AND "storm," this article would be retrieved "The Perfect Storm: A Review of the Literature on Increased Noise Levels in Academic Libraries" even though it has nothing to do with storm damage).
A savvier way to search is to use subject searching. Subject searching takes advantage of the power of a controlled vocabulary. When you search by subject, only the subject headings of a record are searched. If you have the right term, all of the results should be relevant to that subject (in other words, if we used subject searching instead of keyword searching in the example above, only articles about real storms and libraries would be retrieved).
A drawback of subject searching is not knowing what words were used as descriptors for the subject terms. This can be overcome by using the database's thesaurus. The thesaurus is basically a list of all the subject terms that are used in the database. Sometimes this is called a subject index. Most databases have a searchable thesaurus so you can identify the correct subject term. The thesaurus can also help you identify alternate search terms.