A few tips if you are teaching in Asia:
use key visuals when you are teaching a concept
always use English in class
write a glossary of key words on the board before the lesson
talk at a n normal speed...do not speed up
and the 1000 and one other techniques you can find at places like Dave's ESL cafe at http://www.eslcafe.com/ideas/
Never give up on kids. If you are reading this blog, you can certainly read English and probably speak and write. How did you learn? Are you soooo smart? Don't you think you students can also learn by listening and practicing? Learning a foreign language is tough, especially the older you get, but NEVER give up on kids!
They can and will learn English if you force them to speak English in your class.