Hello there m45over :) This is an ok essay in my opinion, but its just my opinion. But here are my reccommendations.
Firstly, I agree with EF susan, you use "Duke" way too much. Secondly, you need to be more consistent with your use of tenses. With that I mean that you shift way too much between the past, present and past participle tenses. I think EF susan corrected some of those for you. Next, and this is VERY IMPORTANT. I feel that you can impress the adcom more if you show nd dont tell eg
Being Inquisitive, I approached him and asked him about how he came out with his method of teaching
I would remove the " Being inquisitive" part. By doing that the adcom can infer that you are inquisitive from the rest of the sentence. And you wont come across as cocky or too sure of yourself.
It has always been my dream to go to duke
is too much of a cliche in my opinion. Try and be more original. Has going to Duke always been your dream? Really? Since you were born?
I am sorry if I was too harsh. You can leave my advice if you wish. Other than that, I wish you the best. Plus I would be more than willing to look at some of your other essays if you want.