Finish first, start later
When I was in my 20s, I tried to write a children’s story about two characters called Mr Gumshackle and Miss Leatherbarrow. Looking back, the idea was way too cute, and I was trying to be too clever, and I doubt if anyone except me would have been interested in reading it. That’s part of the learning process, of course, writing badly over and over again until you start to improve. Or, as Samuel Beckett said, “Try again. Fail again. Fail better.”