Let me repeat, with full credit to Nathan Cole (wonderful player and teacher!), practice makes performance (see https://www.natesviolin.com/practice-makes-performance-training-1-3/) . We perform how we practiced. If perfection is only a minute part of how you practiced - if most of your practice time was spent doing it badly, then that is how you will play in performance.
Watch James Ehnes talk about practicing: (https://www.youtube.com/watch?v=6noasTa4eiY).
Strive for the highest possible quality in all aspects of playing while you are practicing, as you would on stage. Condition yourself to always do the best you can. Intonation, sound, phrasing - all should be as perfect as possible.
Don’t let your guard down. Don’t let yourself get away with anything at all. No excuses. None. No “it's OK because I’m tired”, or “it is only a small thing, I’ll fix it later”. None of that should be acceptable. As any performance, your practice time should be spent using the full resources of your mind and body. Do not waste a single moment. Condition yourself to require the very best of yourself in all circumstances.
This habit of mind should include always playing with proper musical phrasing, and with character. Part of your habit of mind should be to always play as a musician with musical phrasing and feeling. Practice everything as if you are in front of an audience engaged in delivering your absolute best.
Never do mechanical, route playing, even when you are practicing scales, exercises and etudes. Music is nothing if not human, and so should be its components. It should never be merely mechanical and soulless. Often it is said of great performing artists that they can elevate even trite music with soulful playing.
It is a habit of mind worth cultivating.