We're probably all familiar with the AA mantra: "One Day at a Time". It's a message of moment to moment forming a new habit in the direction of our choosing. Practicing our instrument can be like this because, to grow, we must show up one day at a time.
It's easy to practice when we're inspired. It's hard to practice when we're thinking about something else. The key is practicing one day at a time. If improving as a musician is your priority and you envision your tasks is just, "Today, I must practice." Then you'll grow.
Setting aside time each day, if we focus on our technique and skills, and accept when our mind becomes distracted, by gently pulling our attention back to the instrument one day at a time, we gradually grow to be more powerful musicians. It's this patience mixed with discipline that allows us to progress. There are no easy answers; it's a peaceful battle against old habits, practiced - one day at a time.