In graphic arts, the fastest way to reset perception is the mirror trick -- just look at your work through the mirror, or, if you're in Photoshop, use Horizontal Flip.
However, the mirror trick never worked for me with user interfaces because the reading diagonal (what's the English term for this?) gets flipped, and various UI conventions such as the OK / Cancel button order get messed up.
For texts, just abstain from looking / editing / thinking about it for at least a few hours, or, ideally, days if you're not under a deadline. Unlike the mirror trick, this approach seems to be universal -- for me, it also worked for many things, including user interfaces and decisions in general.
There are a lot of tricks like this in various fields. One of the simplest ones I can think of comes from the visual arts: when you come to a stopping point, simply turn the paper (canvas, Photoshop workspace, etc.) upside down, and if any of it looks weird from the new perspective, fix that part.
Unfortunately that'd only work for the static parts of UI; I don't know of any better palate-cleanser for the interactive parts of the experience than simply setting the project down for a while and coming back once you've context-switched into something else.
Time off is good for this - for example, when writing, I often set drafts aside for a few days before rewriting.
Maybe closely examining a similar product with a different interface would help?
Or maybe trying to mock up a design how you imagine someone else would do it? Perhaps a competitor?
This might sound obvious, but:
Spending time frequently with different groups of friends with different value systems, each of which (you believe) has an accurate map of different parts of the world.
My experience:
My rationalist friends help me inject more empiricism/anti-happy-death-spiral memes into my church experience; my church friends help me keep other memes like "non-smart people are still worthwhile," "actions perceived as demonstrating character and virtue aren't all just signalling," and of course the "no sex, no drugs" purity meme.
I am in favor of all of the preceding memes but tend to forget each of them over time if I spend too long in a community that doesn't observe them.
I grew up a very religious child, and I kept the no-sex meme long after I stopped being religious. Can you explain why you value no-sex purity?
The guy who taught me how to eat sushi a couple months ago explained that I should get a slice of ginger before trying a different kind of sushi in order to "reset my taste buds" (probably broscience) and feel the taste anew (it works). That's also the exact problem that programmers face when trying to design user interfaces: after looking at the thing for a long time, they grow blind to its shortcomings. A visual reset would come in handy. I imagine that resets could help in other areas too. Does anything like that exist? Cogsci majors, help!