Getting the most out of libraries

I know how to include libraries, and use the common functions, but am interested in receiving guidance on how to determine what functions are available within a library and then of course, how to use them correctly. Does anyone know of web resources that explain how to analyze the contents of a library and understand how to use it's various functions?

Unfortunately the best piece of information is a 'technical document' written specifically for the library. Otherwise your only options are to delve into the code yourself, or scour the net for other peoples projects using the same library.

If the library is a collection of functions, hopefully there are well defined names used for functions or plenty of comments to explain its functionality.

In a class look at the stuff in the public section, member functions, member data, non-member functions... Then trial and error to piece it together.

Post the library if you need someone to give a brief outline of its functionality, might be people that have used it too.