As a student, I think one of the most important things is to feel completely relaxed and at ease at the keyboard. When I started I was very ambitious about what I wanted to play, and always wanted to be working on pieces way above my level; eventually I could hit all of the notes at least once in a while, but I could never play them for anyone else, because I was never comfortable. Then I spent a year playing nothing but damn easy pieces (Music for Millions Easy Classics, that sort of thing), and after a year of that I felt so comfortable and at ease that playing for others is not hard at all (just had my first paid gig subbing for a church organist), and now I'm able to play more difficult things with a lot less stress and better relaxation. It's definitely worth it to be patient and put off learning the higher level things until lower level pieces feel very easy.