What (I think) is my problem at my piano (other than lack of a teacher) is that I can't seem to put full concentration on whatever I'm playing, resulting in almost carless mistakes. I can tell when I'm fully concentrating - after I finish a piece, with few or no mistakes, I end up sweating and dry-mouthed, which I don't notice while playing. But this happens rarely. How can I achieve such a good state of total concentration more often?
*eagerly waiting for an insightful and elaborate response from Bernhard*