I agree with the answers so far, but also make sure you play a variety of classical music. Personally, I dislike any music pre-1850, but find that learning a three-part Bach fugue really helps my technique. Playing the pieces you enjoy is then easier, and you can add more expression to them and it is more rewarding. On the same point, let your teacher know what kind of music you like.
Also, as well as challenging yourself with the occasional difficult piece or etude, try to master an easier piece to perfection. An example of a piece which sounds terrible if simply played note by note and with bad technique but is not necessarily hard to play is 'Menuet sur le Nom D'Haydn' by Ravel.
Its very boring, but try to learn one scale or two- it really helps with pieces and scales are the ultimate technical exercises. If you are serious about piano playing, learn a Czerny exercise or two, though unless you are really serious I would not recommend doing so at your level.
Lastly, do not think of practice as a chore; it should be something you enjoy.