To me, the secret is being okay with failure, learning from it, than trying again.
I've heard this called the Feynman technique before. Pretend as if you know what you are doing and what to do, than start doing it as if you knew how, and each time you fail or realize you don't know how to proceed, stop, go learn only as much as you need too unblock your next step, rinse and repeat.
It's a really good way to eventually learn and succeed, while wasting as little time as possible.
The issue is that, when it comes to software development, where you need to build upon what you've done before to keep moving forward, the risk is that all your prior steps weren't considering your next ones, and at the time you built them you didn't really look further, you were focused on figuring out only the next move pretending you knew it all.
So in a startup setting, it kind of means that if you follow this technique, you'll quickly learn and figure out what and how to do things, but you'll also fail a lot, and those failures will pile up, and all you built during that process might not end up being usable in the end, as it could be a monster of tech dept, limitations and bad decisions.
That's where a lot of startup have a "big rewrite" phase normally.
This still works if you are okay with having that big rewrite/refactor phase, and as long as your monster was still good enough to carve you a big customer base or investor interest, that'll be patient enough to wait for your rewrite.
I'm not sure how to summarize this, but there are some problems that each step you take you've now advanced closer to the solution, so it's fine to not think holistically about it all, but focus one thing at a time. While there are other problems where that only take you so far, and at some point you have to think holistically, do I need to do anything about this foundation in planning of what I'll later build upon it? That kind of thing.
But I think often what happens is people are too afraid to fail, and they start thinking holistically, except they actually are not expert enough to be doing so. So they start thinking all hypothetical, imagining the problems that will come, and that all ends up a waste of time.
If they'd tried, tried and tried some more, then they'd actually have learned a lot, and now would possibly be on a place to actually think holistically.
I heard a pretty good saying on that:
"The difference between the master and the beginner, is that the master has failed more time than the beginner has tried".
I think it's by Stephen McCranie