One of the most important thing a composer can do is listen, listen, listen. Listen with score, listen without score, listen with eyes shut, listen with score again, listen as you conduct, listen as you hum the main themes - you'll learn so much by informed listening!
The informed and knowledgeable composer should be able to identify the following pieces. Test yourself!
Name the composer, the period of time, the name of the piece, and any other interesting relevant information.