P.S. I note that all the talk is about classical. Does anyone play any rock? House of the Rising Sun by the Animals was my favorite song to play and I have a difficult Stairway to Heaven by Led Zepplin that I really want to learn...down the road. I do have classical pieces that I will diligency be playing though.
I play everything.
Other than classical I like celtic music, rock, pop, boogie, blues, twist, ballads, new age.
Also I like disney tunes, video game music and even play dance music (yup, on the piano!)
The point is realizing that all music is based on chords. Classical music, like any other kind of music, is chords over a melody; the difference being that those chords are arranged in interesting and creative ways. The only exception to this rule is baroque music where you have a melody over a countermelody. So the more you understand the foundation of music the more you can divert from the classical standard maintaining the same care and precision though.
That's why you must not play something you don't understand. For many pianists playing is like reading aload a russian poem. You might pronounce it properly (because of the phonetic signs) but you don't understand anything of what you're reading.
The most important things you must understand of a piece of music you're practicing are:
structure, rhythm, pulse, phrasing. That's why the best way to learn piano is to focus on things you can play almost instantly versus stuff you need months to slightly master.
You must focus on things that are immediate enough to provide you enough musical information that make sense to your musical senses.
If you're interested in anything non-classical you might want to buy a book of chords and stard practicing them. The buy a fake book and start arranging your chords. You will begin with block chords, then broken, then arpeggio, than straight beats, then dotted rhythm and so on. You progress by adding small changes to what you already know well. The small changes, progress after progress, become bigger and bigger and last thing you know you're already arranging and harmonizing instinctively with good technique.
As for technique I would begin with some posture exercises.
Find the best way to produce a sound at the piano and don't give for granted that all you need to do is sitting and depressing a note. You must feel grounded on the bench, you must feel confortable when playing, the arms need to move with ease, tension must be released and never be accumulated.
Topic: Ledger Lines - ACE