One possible version:
We are supposed to be grateful to people who are always there with us because they are the charming gardeners who make our souls blossom.
My English teacher is such a great soul, to whom I owe many thanks. During the previous study, my biggest flaw must come to carelessness, which worried me a lot. To make matters worse, I was too anxious to seek the fundamental reason for my failure. I just dedicated myself to huge amounts of practice, regardless of repeated mistakes. Fortunately, my teacher noticed it and offered to have a long talk with me. Having been persuaded to change my attitude, I finally got the right way to rid myself of carelessness and gained confidence as well.
I am grateful to my English teacher for all the support he has given me, which has made me stronger and a better person.