Escape PERFECTIONISM - Delegate the judgment
Perfectionism is commonly cited as one of the main enemies of progress. Indeed, if it keeps you from finishing things and moving ahead in life, it needs to be cut back to allow yourself grow. But people who have this problem usually cannot really stop themselves from striving for perfection, this is not something they can choose not to do. So my suggestion to them is to delegate the judgment of whether their work is good enough to others, rather than trying to decide themselves. It is, of course, vital that your work is of high quality, but you do not want this feeling (rather than reality) block you from finishing a project and moving on to the next one.