Look at your work as if...

...you don't know anything about design. I think this can also be seen as stepping back from your work and getting rid of the parent-child relationship with your work for a second. A designer should be able to admit that some of his works aren't as brillian as he wants them to be. We should also be able to look at our work as if we are looking at someone else's. We are very good at criticising the works of others, but not so efficient in critisizing our own. The bottom line of this advice for me is to learn how value your work without becoming obcessive.