I am a native speaker and have been involved teaching Mandarin more than 15 years. I can teach you how to read/write (traditional character particularly) and practical conversation in all areas.
I can teach students from new beginners or advanced learners.
I can fully adapt the culture into language learning since I have lived in Taiwan more than 20 years before I settle down in US.

I also know Taiwanese Dialect as well and be able to teach the conversation too. This Dialect has been used in my whole life too.