When shifting on the violin, just place the finger on the next note you want to shift to on the string. If you're shifting to a higher note on the same string, you shouldn't move the finger that you used from the note before. Keep it there, and then press your finger on the next note. If you're shifting to a lower note on the same string, let go of the finger that you used from before and press the next note.
Explanation:
If you have any other specific questions, you can ask.
