I need help on the violin?

Vibrato is a technique to enhance and enrich the sound of a note, usually ociated with notes of a value of a dotted quarter note or more. To achieve vibrato, you must fix your wrist in a bit of a curve over the neck, but not a sharp angle, for that will cause some joint pain in the future. Take the finger position you need for the specific note (1st finger, 1st position, 2nd finger, 2nd position, etc). Once you have done so, start moving your fingers back and forth, up and down. Now, what a lot of people sadly do, and make as a habit which prevents them from mastering vibrato, is going left to right. now, go back and forth a little faster, making sure NOT to move your wrist left or wright, but rather stiffly up and down with the movement of your fingers. Now, do it faster, but gracefully, at a moderately slow tempo. You WON'T get vibrato on the first try (it took me about 30 tries to even get anything close to the right sound), so be prepared to practice this technique a LOT. The problem occuring as to why your violin shakes can be for two reasons. 1: Its back and forth, side to side, if you do that, the hole violin will shake, and you won't get the rich, smooth tone you're looking for. 2: Again, you need to be positive that your grip on the violin is 100% foolproof. If you have a dangling wrist or loose fingers, the technique won't work. Of course, you don't want to press too hard, as that would create a rougher tone. Hope this helped :)