Need help with Basic Technique and Posture...

[DivineWings]

I took lessons for probably five or six years throughout elementary and some of middle school.  At first I was excited, then I hated it.  I quit for a couple years.  Then, in my sophomore year of high school I started listening to progressive rock and got into keyboards.  It really inspired me to become a musician, and I learned tons of theory and became interested in composition.  Slowly I became interested again in straight piano too, and now I love playing on both instruments.  I have learned how to play the notes of moderate to moderately hard passages of keyboard and piano songs (fingering and whatnot).  However, a few months ago since I have started taking lessons again, I have been informed by my teacher that my technique is not where it needs to be, and she's absolutely right.  I have developed some nasty habits during that hiatus of playing without a teacher (slouching, flattening fingers, unflattened knuckles, elbows in, wrist too far away from or not parallel with the keys, etc.).  For my college audition I excelled in every area except my piano skills, which are not where they should be, and it would be great if I could straighten out some of my technique errors before I go off.

Whenever I start to play, I make sure to START in the right posture, but as I go through the song it all falls apart.  I can see what's happening but I can't fix my technique, the habits are too strong.  My teacher says I can play the songs, but look badly while doing it, and will not be able to play any really advanced songs with my current technique.   

What can I work on to help my technique?  Any particular exercises?  What should I think about when I sit down at the piano?  Any help would be GREATLY appreciated, I don't know what to do...

[gosch]

Try Alexander-Technique lessons. They should match your problem perfectly!
AT focuses on bad habits.
Also try to identify any other bad habits (unnecessary muscle-tension in places not needed for some task...) in your daily life, e.g. posture in front of computer.
Work on that too, away from piano.

But be aware: there's no quick fix for this!
Be patient... very patient