Pitch- key, countour, register etc
Duration- length of each note etc
Texture- layers, thick/thin, high/low etc. etc
Structure- ternary/binary, ABABA etc
Tone Colour- what sound is made from the instruments, how is it played, what can you listen? etc. etc
Dynamics- tempo, sound markings etc. etc
Make sure when you mention specific bar references and talk about instrumentation.