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.