This post is also available in: Japanese バージョンはこちらI use 《新实用汉语》 New Practical Chinese Reader series (2nd Ed) by Beijing Language and Culture University Press – the authoritative Mandarin textbook for foreigners. An all-round textbook that builds up the four essential skills – listening, speaking, reading and writing. For pre-intermediate and above, I also use 《汉语速成》 Short-Term Spoken Chinese series. If you have your preferred textbooks, feel free to let me know.
For complete beginners, explanation will be in English, but I make it a point to use Mandarin whenever possible, and especially terms and expressions students have learnt, so that they get used to the sounds of Mandarin as quickly as possible.