I am glad to give you advice on the customs of giving gifts in my country.
Firstly, I think you need to find out what your Chinese teacher likes. Choosing the gift that your teacher is interested in is a good idea. Secondly, don't pack the gift with black or white wrapping paper, because black and white aren't considered to be lucky colors. Thirdly, don't buy your teacher a clock, a pair of shoes, or some pears because these have bad meanings in Chinese when giving a gift.
I hope my advice can help you.