Go EASY on yourself! Practice is a science AND an art, and sanity and satisfaction come first!
Short practice sessions most days is better than longer practice fewer days
End with something easy or fun. Start with the new/difficult/focus oriented items, or sandwich them in between easier things
Slow and careful wins the “race”! It is always better to do one or two measures the best you can (considering also boredom, of course, so switch tasks as often as needed).
Practice makes PERMANENT NOT perfect!
CHECK position before playing (and sometimes in the middle)!
Resistance to practice generally doesn’t mean that the instrument isn’t a good fit or that it is time to quit- but you have to be a bit of a detective to tease out the “real” issue sometimes. See here for more.