I started out as a "fly by the seat of my pants" quilter, and stayed that way for many years. I have thousands of un-matched seams and chopped-off points to prove it! Over the past several years I've become more aware and careful, and my projects show it. I have only come up with a few rules:
Always close the rotary cutter. Emergency room visits are expensive!
Always turn off and unplug the machine when walking away.
Never sew over a pin.
Press between each step of piecing.
When I'm not having fun, put it away for now. (This rule does not apply to basting the quilt. Ugh!! Basting will never ever be fun.)
If I am laying out fabric for a new quilt and one looks like it just does not "belong," get rid of it now. It will continue to nag me and eat my brain and I will eventually hate it in the finished quilt. Just trust my gut and get rid of it now!