Sometimes we put up barriers when we write. This is different for everyone. Some of us analyze too much, while others plan too much. Yet some may strive for perfection before moving on. My barrier is the analyze thing. I question everything. Not that questioning things is bad to do. We should do that, but when you continue questioning whether what you wrote or in which place a scene/scenes was put, it takes up precious writing time.
Another author I follow and get advice from, told of a first time writer working on his first novel. This young writer asked his advice on his first chapter. So the author read the young writer’s first chapter and ended up being very impressed with it. He asked for more. The young writer didn’t have anymore to show, as he had been working on the first chapter for months trying to get it just right/perfect. The author shook his head and told the young writer to stop striving for perfection. Why? If you do that, you will never get your book written. As long a time it took him to get chapter one finished, he could have had multiple chapters finished had he focused more on getting the story out.
The first draft doesn’t have to be perfect. You just need to get the story written. When that first draft is finished, THEN go back to square one and change what you don’t like. This may be difficult at first, but with practice of letting go and letting the story unfold as it comes, perfection will take a back seat eventually.