Some YouTube Coaching Tips…

http://www.youtube.com/watch?v=V4ldi3h-KWs&feature=fvsr

More general…

http://www.youtube.com/results?search_query=badminton+coaching&oq=badminton+coaching&aq=f&aqi=g10&aql=&gs_sm=3&gs_upl=411l5042l0l5481l16l16l0l8l8l0l339l1047l0.2.2.1l5l0