Reference works can save you a lot of time. They have done the work of compiling information about a person or topic for you and can help you frame your research question. They also have useful bibliographies that can jump start your research process.
There are many music dictionaries and encyclopedias. Depending on what topic you are researching you may need a very specialized one or a more general one. A list of selected online and print dictionaries and encyclopedias to get you started can be found below. You can also search the library catalog for your topic and "dictionary" or "encyclopedia" (e.g. latin american music encyclopedia) to see if we have one that is more specific.
When Grove doesn't list the person you are looking for, or doesn't include very much information, you can try using the biographical dictionaries listed below.
In addition, there are also book-length biographical tools called bio-bibliographies, which is a bibliography devoted to one composer or concept (like string quartets). They list books, journal articles, and other information about a composer. Sometimes these books are called "guides to research" or "research and information guides". They are typically located in the ML134s in the Reference collection.
Sometimes it can be difficult to find biographical information about composers who are still living. Some good sources are publisher websites and interviews (either online or in newspapers and periodicals).