When I learn a new piece, there is always a challenge to get it “into” my hands , my head, my being. Playing a familiar piece, (for me one is Debussy’s 1st Arabesque) I am able to get the best sound from the piano, and my coordination flows with the phrases. Even after working on a new piece for months, I still am playing “notes”, don’t have the satisfying sensation of sinking in and becoming one with the keyboard.

To play a piece properly, a player needs to have the sensation of “painting” the sounds. To do this, there needs to be a deep knowledge of all aspects of the piece.
There needs to be a long period (at least several months) of practice without the score. Take a break with the piece once it is memorized, don’t play it or look at the score for a week. Then, play it through without looking at the score, any places needing work will be obvious!
Play the piece through 4 or 5 times, aiming for perfect note accuracy. Use the metronome, no pedal, and no score. Playing the piece should feel so automatic that you are not thinking of getting the notes, you are just feeling the pulse. The metronone helps with this.
Go back to the score and correct sections with wrong notes.
Practice with the score once the notes are mastered by memory, watching every one of the composer’s markings.
Perform the piece often! Perform for friends and just for yourself. Think of performing and practicing as 2 separate ways of playing. When performing, have fun with the music.