How can I write without self-consciousness?

Dear Literary Ladies,
Now that my writing has seen the light of day, it’s hard to work without feeling like the public, the reviewers, my peers, and my editor are looking over my shoulder—all competing with the inner critic! How did you manage to work without self-cousciousness, knowing what's been said about how you could have done things better or differently?

Those critics or well-wishers who think that I could have written better than I have are flattering me. Always I have written at the top of my bent at that particular time. It may be that this or that, written five years later or one year earlier, or under different circumstances, might have been better for it. But one writes as the opportunity and the material and the inclination shape themselves. This is certain: I never have written a line except to please myself. I never have written with an eye to what is called the public or the market or the trend or the editor or the reviewer. Good or bad, popular or unpopular, lasting or ephemeral, the words I have put down on paper were the best words I could summon at the time to express the thing I wanted more than anything else to say.

—Edna Ferber, A Kind of Magic, 1963