When you are learning the tones, your teacher should show you hand movements that go along with the tones (e.g. an upward motion for the rising tone or a downward motion for the falling tone.) always practice the words using the motions. The Chinese "r" is pronounced with the tip of the tongue behind the bottom teeth. The differences between "zh, ch, sh" and "j, q, x" is that the first group are pronounced with the tongue tip pointing down and the second group with the tongue tip pointing up. I hope this helps.