Without perseverance, many writers give up before reaching their goal of publication. Take it from me, if you don't persevere, you'll never receive that first letter of acceptance.
As a small child, I spent all my free time writing stories, illustrating them and binding them into small books. In high school, I convinced my English teacher to allow me to write a novel in my senior year rather than do class assignments. After graduation, I enrolled in a correspondence course and sent off my first manuscript. With a fragile ego, when I received my first rejection letter, I decided it was my last. I put away my goals and fulfilled my aspirations by writing lengthy letters to friends and being creative with my business letters.
Finally in mid-life, I began writing grants for local non-profits. When I realized that I was being "paid" to write, I decided to try another correspondence course. This time, through perseverance, I landed my first contract for publication of a children's story.
The one thing no one told me as a beginning writer was that even great writers experience rejection. I hear it repeated all the time now. Writers talk to other writers. The internet is a fabulous networking tool. No longer do we operate in a vacuum. Many published writers tell of sending off a story, ten, twenty, fifty times before acceptance. Not all manuscripts are published, but rejection shouldn't squash your creativity or your desire to submit.
If you don't keep trying, you'll never get that first by-line.