When I've done some digital creation work in Photoshop, I also run into this problem. Rather than turn to others (though I do appreciate peer review, I don't always heed the advice given), I step away from it. I don't look at it. I close the file and don't even think about it for a full week.
Then I come back with fresh eyes and spot new things in the photoshop file. I say "oh, that effect is gaudy," or "did I really miss this detail?" and keep working until I think I'm done or nearly so. Then repeat the 1-week-cooldown.
I would imagine the same works for photography, as long as you're not on a deadline.