Learning to pronounce Russian "R" is the only difficulty in Russian phonetics for Chinese speakers (and for little Russian children as well). Try to achieve a vibrating sound (like a helicopter) with your tongue. You don't even need voice - only air flowing out through you mouth. When you can thus imitate the sound of a helicopter then you are able to pronounce Russian R by adding your voice.

I would advise to start with "tr", like in "трактор". For some reason it seems easier for Chinese students. and here is some advice, which, I think, might be helpful: http://learn-russian.language101.com/how-to/how-to-roll-your-russian-rs/

A Tiger growls "ррррррррррр" :) It's the same like in russian "R"

Just say words - river, rage, room, rocket, radio, rise The first sound "R" is sounds just like " Р " in russian. russian words for example - рыба, рог, ромашка, рука, there are a lot of examples.... Enjoy