Joining some mandarin trainning schools is not the best way to learn Chinese, unless you enter some real good schools and universites, such as BLCU, Peking University. You can find more from the home page of the web, just try “mandarin” ,“ learn Chinese”, or click the Education.
mandarin is really very difficult to learn. There’s many books and websites which teaching mandarin, you can find them easily. Such as www.mandarinspace.com,.
Recall your childhood time, how to learn abc, then use it on mandarin. First of all, you have to try to not use English when you learning mandarin. Talking with Chinese, or share house with Chinese people when you rent apartment.