through what to improve ur technique

Depending on your level of badminton ability, you might like Peter Rasmussen's coaching videos on http://badmintonlife.com/. He explains all of the essential shots in a badminton player's arsenal as well as looking at some more advanced techniques such as reverse slice and the jump smash. Movement, grips and the serve are also covered. Peter explains each aspect of the shot really clearly and breaks each shot down in to numerous "stages" so it isn't too much to take in at once. There's a "sample video" of the Essentials of Technique course on YouTube (or just click here); this one covers the jump smash. My one criticism of Peter's coaching videos is that at times, they go a bit slowly for my liking. They seem to be designed for all ability levels; this isn't necessarily a bad thing but if you're a more advanced player, you might find that, like me, he seems to take a while to explain even fairly simple ideas.

I have also used the Badminton England DVD. Again, each basic shot is explained clearly by top professional players but if I recall correctly, it shies away from some more complicated badminton techniques, I don't seem to think that slice was covered at all. Some shots are presented using animations as well as video footage. I also found the pace of the instruction in these videos to be a little slow (not as slow as Peter's though) but the interviews between instructional videos and the music make watching it all in one go quite an annoying experience. If you're just looking for tips on one or two shots at a time (as most people are), it'll probably be fine but watching the whole thing is really quite frustrating. There are videos taken from this DVD on YouTube but I'm not going to link to them due to the questionable legality of them being uploaded there. If you want to watch them, I'm sure you'll find them easily enough.

Overall, both are fairly nice products (if a little overpriced). Peter's course has the benefit of being online so you can access it on anything with an internet connection and flash support and you receive your videos almost instantly. I suggest you watch a sample of each before committing to any purchases though. For more personal coaching, you could try recording a video of yourself playing, uploading it to YouTube or an equivalent site and linking to it in the "Post videos of yourself playing" thread.

 

To add to Dan's suggestion,

The best is to hire a coach. There should be plenty of good coaches in Guangzhou.

There is also a series of coaching videos done by Zhao Jian Hua which I find helpful. He approaches the video by addressing the common mistakes and habits of amateur players rather than taking the lessons from ground up.

Other resources are Gollum's excellent Badminton Bible.

 

Not too sure about the devoted coach part... I'm sure you can join a class or something. I tried to learn from videos and while there are improvements, I never really got much better until I got coaching. It's always good to have an expert eye on what you are doing to see what is wrong. I'd approach any shop in the vicinity of your badminton hall for contacts. For coaches, you just have to try to know...

Reason I liked ZJH/XJ's videos is they point out common mistakes by amateurs like us. Direct coaching videos are useful to get the general idea but tend not to pay enough attention to details.