Writing good quality program notes can be very difficult, because information about pieces (particularly more modern ones) tends to be hard to find in one place.
There are many sources that you can use to find accurate information about the works you choose to perform on a recital or concert. You just have to know where to look!
Sample sources could include:
|Google and Wikipedia||A recording of the piece|
|Music Dictionaries||Journal articles|
|Grove Music Online (now Oxford)||CD liner notes|
|Other music encyclopedias||Classical Music Library|
|Composer Websites||Naxos Music Library|
|Blogs||A score of the piece|
|Repertoire Guides (e.g. Daniels)||Composer Bibliographies|
|Diaries||RIPM Online Archive|