Once you've recorded yourself and listened to it a few times, focus on one area that you made the most mistakes in. Was it grammar? Vocabulary? Was it coherence? If you were telling a story in your answer, for example, but you used the present tense several times, you should practice the answer again, concentrating on just improving the usage of the correct verb tense.
Then record yourself again. Listen. Did you notice improvement?
By focusing on just one area to improve, you're going to make a bigger impact on the quality of your answer than if you just try to fix every mistake you made.