To even get to a mindset, one needs to follow certain steps:
1. Have a space dedicated for practice only.
2. Turn all electronics off (except the iPad if used)
3. Have a well defined technical routine — Open strings, Scales, Arpeggios/Doublestops
4. After solving technical aspects of the piece (fingerings, bowings, dynamics, phrasing), play it many times through, just like on the stage.
(optional) Use a timer, e.g. 50 minutes at a time, plus a 10 minute break