Schmitt exercises, one hand alone. Ten minutes a day the first year. one set legato, another staccato. These develop strength and control of the little used fingers 3,4,5. Also they get the subordinate hand to work as well as the dominant one. Rhythm should be even, loudness should be even. You should be able to memorize the ones you're working on by the end of the week. Speed should increase, but never go so fast as to make mistakes. You may give more practice time to the subordinate hand.
These can be downloaded from pianostreet, or I used the Schirmer edition still available for sale.
After a year of that, my teacher assigned me Edna Mae Berman exercises, one a week.
To quote Pink Floyd, How can you have any pudding if you don't eat your beets?