Analyses can point out important structural elements of a piece of music, as well as other unique characteristics that can help a listener appreciate a work.

You can find analytical writings in SearchWorks using subject keywords:  [composer last name] and analysis. For instance, looking for analyses of Brahms' works brings up a variety of results including books about songs, sonatas, chamber music, and symphonies.

You may also look for journal articles about your pieces, in databases such as JSTOR.  Use keywords selectively, and be patient! You'll likely get many more results than you need. You can narrow results by language, and content type (such as "journals")