Tre rule of "ok for now"
When it comes to painting (not very often sketching as it is a rapid kind of expression) I try to go by the rule "ok for now". When something is just that, I leave it, and start with another painting or art project.. When I´m almost done with the painting in the cross over project, I go back to the art work I did before to check if ok for now still rules. If not. I´ll try to adjust it. If it´s far from ok, I´ll paint it over to make room for something new.
I think I go by this rule in many other areas of life. I don´t believe that things are definite or that there is an absolute truth that can´t be changed.