A bit late, I've been off the interwebs for a while, but here goes:

A) Plan a speaking class that actually lets students speak. You don't need to practice your Chinese, your students do, so plan a lesson with minimal teacher talking time and maximum student talking time. The hardest part of being a language teacher is learning to shut the f**k up in class a giving your students a chance.

B) Don't ask and answer your own question, ending your explanation with a rhetorical question doesn't mean that the students agree or understand you. Use comprehension check questions and listen to your students producing the language for themselves

C) Grade your language! If it's obvious that I have a limited vocabulary, don't talk to me like your talk to your friends. Select simple words, slow down, but don't use baby-talk or patronise your students.

D) Describe usage, don't prescribe. Students aren't blank slates, and they probably already have a (patchy) knowledge of what you're talking about. Ask students questions, and let them do the hard work for you. Letting them take a chance and getting it right is a confidence booster, and even if they get it wrong, try to incorporate it positively to feel like they've contributed.

As a language teacher, your ultimate remit is that you act as a facilitator for the students to learn and discover by themselves. Keep them on topic and guide them from their mistakes to the right way. Students can learn long lists of words by themselves, but what you are actually teaching is conversation skills, so set up a classroom environment that facilitates conversation rather than rote learning.

Some general principles here for teaching English that can be transferred to teaching Chinese: http://iteslj.org/Articles/Zhou-SuccessulTeacher.html