Following these steps to get started with your research about a piece of music:
Use Grove Music Online and find the piece you are researching in the works list under the composer entry. You will find basic information about date of composition, the first performance, dedication information, orchestration, etc.
Use composer biographies, which are located in the ML410 section of the Library. Once you find a book on your composer, search the index at the back of the book for the title of your piece.
Naxos Music Library includes online access to recordings and liner notes. Use recordings of the piece you're researching and check the liner notes for relevant information. If available, the notes will appear on the left hand side of the page as a PDF download.
If researching a more contemporary composer you may need to use online sources such as: the composer’s website, liner notes, musical score, association website (e.g. Canadian Music Centre). Be sure to check that websites are sharing reliable information.
The following writing guides include chapters on how to write program notes.