i am learning dutch my-self with dutch methods. be careful with teatcher from belgium, he may teatch you belgian dutch, flamish. "r" is not so difficult to pronounce. question to vibrate your tongue.
Finding a dutch teacher is atmost rare in china. even learning dutch yourself you wont understand people what they are meaning. Dutch Language isnt a static language like Chinese. For example Belgian Dutch and Dutch Dutch. Belgian Dutch (Flamish/Vlaams) they still using the old "dutch". Sometimes its hard to understand them but we can understand eachother.
Yeah the R is pretty hard (I can do it 5 min nonstop :P) and the G of SCH is pretty dangerous also :P, its like the sound before you gonna spit. :P