There are two things that I think have made the biggest difference for me
One - I started doing one-day mystery quilts. Merry Mayhem has one every New Year's Day. They are simple enough to be completed in one day, but complex enough to look good. paintmejudy here on the board also does mystery quilts (mystery train rides) and she has excellent instructions. By doing a mystery quilt, I'm focussed only on the current step and that seems to help me pay more attention. Finished quilts are often a pattern that I would not otherwise tackle.
Two - I joined round robins or block swaps. When sewing something that I know is going to become part of someone else's quilt, I take special care. This has translated into building good habits.