One method that does a good job of giving adults flexibility and choice is the Play by Choice Adult Piano Method by Fred Kern , published by Hal Leonard Publishing . For example, the Play by Choice book deals with note reading from different approaches and lets the adult student choose which one is most comfortable. Many of the rhythmic problems of initial cross coordination are dealt with by using the concept of finger taps away from the piano, on a computer desktop or table top, thereby removing the focus from wrong notes, but working on the different rhythmic problems and coordination problems before they are taken to the piano. Subsequent repertoire books in the series give adult students a substantial choice of what pieces they would like to learn. Before any repertoire is done, the student is taken through a series of warm-ups and prep.
Exercises help prepare for the playing of the individual piece.
Our advice to adults for practice techniques is much the same as that we would give for children. Here, you have an advantage in that you are probably more focussed and motivated than the average child student. It's best to try to practice when the kids are not around, so that you avoid interruption. Learning to play piano is more than just playing the notes. If you are working on a piece, try to listen to a recording of it.