Fairly early in my career, I saw that tendency to hold on and to continue to rewrite even though I couldn't see anything that would improve my writing. In a month or a year I could probably do this better, I reasoned, but not now. That's when I made a commitment to myself. When I worked on a manuscript (and in those days was part of an editing group) and couldn't find anything more to change, I sent it out. I had to say to myself, repeatedly in the early days, "This is the best I can do at this stage of my development."
Even if my manuscript isn't perfect,
when it's the best I can do, I know it's ready to send out.