5) Go slow, go fast, go slow again.
The hallmark of erratic driving is a great test of true grasp of technique and timing. Take a short piece or study that you have roughly under control, and set the metronome at quarter or 8th notes. Play straight through, even if there are mistakes or reversed bowings. Then keeping the metronome at the same speed, play the whole thing at half tempo, which will make the clicks 8th or 16th notes. Pedantic? Yes. Annoying? Oh yes. Like vitamins for your playing? Definitely. After the half speed run through, return to normal tempo. Finally, reduce the metronome setting by half, so you’re only hearing every other beat, or in the case of compound meters counted in 3, the downbeats. This kind of work really cleans up the slop in every aspect of technique!