Touch with the tip of you tongue in the middle of the palate, then produce the sound of a cat, or an engine "rrrrrrrrrr". your tonge must vibrate, vibrate very much, thus there will poduce sound. rrrrrrrrrrrra,rrrrrrrrrre,rrrrrrrri,etcrrrrrrrr. he,he. I wish you luck

the best way to learn how to pronounces that is watching a film and paying atention y that pronunciation. the jocoso answer is easy to understand for a spanish speaker,and "rr" neither sounds like "car".you have to listen how to pronounces that's the best way to improve. i hope be useful! luck!