How are two examples of the same piece different or the same?
What aspects of the following are relevant in assessing these performances?
Articulation (legato vs staccato . . .)
Other expressive elements
Time and place of performance
Write down factual statements about what you're hearing, without expressing your own opinions and assements, then . . .
Formulate opinions and assessments based on your own listening experience(s).
Read what other musicans have written about music. Books are identified in the "Books and Articles" section of this guide. Of particular interest will be Pleasures of Music / Barzun (Classic), Classic Essays on Twentieth-Century Music / Kostelanetz and Darby (Contemporary), and Best Music Writing 2008 / George (Popular).