Muso
Hi, i play the violin aswell!
I have had a similar problem to yours. What I did was play music that i liked ( not the piece you play that you have problems with) and in these other pieces, practice shifting and some other techniques for about an hour a day for a week or so and then by the time you get back to the piece you had worries with, your shifting should be good, vibrato good, good sound production but maybe you may have slight issuse with internation. Email me on miss_mac92@hotmail.com if you want to talk some more.