Perfect is the enemy of Good
I mentioned this suggested aphorism to my father, who is a design engineer, and he responded with a slightly less absolute one they use in his shop:
Better is the enemy of Good Enough
These all remind me of the saying that floated around the shop when I was doing technical theater for the summer reperatory program at the University of Findlay (often said to me, then a Physics major, following the phrase "This ain't rocket science"):
Done is Good
So I offer them to you, and myself, as a reminder not to be so worried about getting something right that you don't get it done at all.