I've just made 5 Roman blinds for my house. The first two took a lot of swearing and are a bit wonky, the third involved a lot of unpicking and resewing and the fourth has copious quantities of my blood spread between the 4th and 5th bar where I stabbed myself with a pin and didn't notice until it was too late. The fifth is just about perfect and took a quarter of the time of the first blind.
In other words, I got better with practice.
Same with writing. It's a lovely idea that writing just pitches up on the page without any effort on the writer's part but It's Not True. If you do a lot of it (of anything!), you get better and more efficient, and you have confidence that you can succeed.
Persist. Practice. Get better. Succeed.