In her altogether fantastic advice to aspiring writers – which applies equally to artists of all stripes – novelist Ann Patchett offers this:
I never learned how to take the beautiful thing in my imagination and put it on paper without feeling I killed it along the way. I did, however, learn how to weather the death, and I learned how to forgive myself for it. Forgiveness. The ability to forgive oneself. Stop here for a few breaths and think about this because it is the key to making art, and very possibly the key to finding any semblance of happiness in life. […] I believe, more than anything, that this grief of constantly having to face down our own inadequacies is what keeps people from being writers. Forgiveness, therefore, is key. I can’t write the book I want to write, but I can and will write the book I am capable of writing. Again and again throughout the course of my life I will forgive myself.
Read more here – it's well worth it.