In the last couple of years I have managed to achieve a noticeable improvement in my overall piano technique by focusing on scale and arpeggio excersizes. One piece of sloppiness remains – octaves. I am often sloppy in RH and worse in LH and I have difficulty doing accurate boogie woogie LH broken octaves. I have managed to scrounge up some useful octave exercises to address this and they appear to be helping. (though I am just starting this) Octave practice is pretty exausting so be careful and do not overuse arm motion as it tends to tire you out faster and negatively impact accuracy.
1. Regular and slurred octave scales CD DE EF FG GA AB BC C
2. Octave arpeggios varying the accent points
3. Single note octaves toggling from eighth-triplet-sixteenth
If you are feeling brave there is also the czerny octave studies [pdf]. I have not made it far with these yet.