Practice is a dialog with an instrument that consists of different stages. I'll point out just most evident of them.
1) You should have a precisely adjusted conception of a piece you perform. Otherwise I find no sense to start working with a text. This conception can later change, but it's strange if it doesn't exist at all.
2) Then comes the detailed study of the fingering which is based on your conception.
3) Scores' knowledge: it should be an easy job for you to write any fragment of a piece from memory.
4) While playing a piece you should name each note inwardly and accompany it with a visual control of your left hand.
5) You should be able to "play" a piece in a slow tempo without an instrument, but feeling it in your hands, looking in scores only and naming notes aloud.
6) ) You should be able to "play" all your program without scores and without an instrument with your eyes closed, naming notes inwardly and feeling a contact with an instrument.
It is a minimum.
It doesn't concern a music, but only a skill. Otherwise you'll have no freedom. These are only several examples of a practice while meeting which you have a chance to feel yourself freer. And also these is a technique. And it's also a minimum.
This should be a standard. At least for me it's a standard for last 15 years. Plus a technique and a literacy. And then it's possible to do smth if there is a background.