Truly you need to start to think of what you draw as a three dimensional object, those people saying "Draw boexes" are not kidding
My suggestion is to leave the tablet for awhile; grab a pen. Yes not a pencil, draw with pens. This will force you to think before you lay down every line, as whichever can be erased our brain sees as wrong.
The enxt major important thing is, get an easel and draw on large formats, this will get you out of this little stuff. Remmember from general to detail, that is for example Form, Gesture down to what type of hair this gal standing in front of you has got
, get the point? Hope i helped.