Among the most useful pieces of advice I've ever come across is one repeated often in many forms, but it took Milton Glaser, the artist and graphic designer, to give it to me in the most succinct form: Solving the problem is more important than being right.
Solving creative problems can be even more difficult than solving worldly problems, because the very act of creating something is an ego-bound action. There's really no such thing as egoless creation. The most any of us can do, I guess, is train ourselves not to let our ego get the final word or the upper hand.
It's hard to figure out what's best for the work, to do what's right for the work instead of what makes you feel right. I am no expert at this myself, but I have picked up a few hints along the way about how to take a more egoless approach to one's work.
"Inspirational bridges" — that's my term for those individual little things that often spark off a story. A single cool image, a conceit that seems separate from anything else but is nifty all the same. A lot of the time, those things exist to get you over the first creative hump, to give the wheel that one good turn it needs the first time. By the time the wheel's turning freely, you might find those Cool Things you fixated on as the entry point for the story don't really fit in it anymore. You can ditch them. Or, if you really can't bring yourself to ditch them, you can tone down their presence in the story. Rather than burn those bridges outright, you can just rope them off.
When you finish a draft, put it away and do everything in your power to forget about it for about a week. Get caught up on your reading; binge-watch a TV series; whatever. Anything as long as it puts out of mind all the internal justifications you've built up for why things have to be the way they are in the story. That way, when you return to the work, those things will feel like someone else's ideas, and thus easier to critique. If you're worried about forgetting something functionally important, do what you ought to be doing anyway with such details: write them down! They only need to be on paper to be informational, not binding.
Dumb and obvious as this seems, it bears repeating. You make the story, and the story cannot exist without you, but you are not the story. What people say about your work is not a reflection of you, and what you think about your work isn't a reflection of you either. It's about some work you did at some point. And this also applies to your own attitude towards your work. You have the capacity to learn from the significance of that work, even if it was only something you did five minutes ago, and which still feels like a part of you.
Once you put something out there, it becomes the domain of the world entire. I do not mean that intellectual property rights are meaningless (we can debate that separately; I'm sure there are vigorous defenses of both sides of that argument). Only that once something's out there, there's no point in trying to call it back into your hands and remake it. George Lucas spent too much of his career trying to do exactly that, and all he did was incur the ill will of the very people who elevated him in the first place. The more you learn to let things go and move on to the next thing, the less making any one mistake (one that might not even be that bad at all) will seem like a blight on your esteemed name.