When in writing, be humble about your work. Don't flaunt it like a diva but do show it to people who love you and care about you and want you to succeed with it. Tell them thank you for reading it. Back with the second "Be" with weaknesses, don't argue with people about what they think of your story. Take it with a grain of salt and see if you can't do something while editing to really take some of their criticism and put it to good use.
The best way to succomb to the humility as a writer is to keep studying up what goes into your story. Keep learning as a writer.
I saw something a long time ago that tells all the professions of a writer because of the studying and learning that goes on throughout this one career.
A writer is a doctor, a mother, a father, a drunk, a student, an airline pilot, a neurosurgeon, a lawyer, and you get the point.
There are stories that I have where I have to learn about brain tumors, historical Italy, sky diving, the Civil War, horseback riding and the care of horses, emeralds, the political society and many more. I have learned so much but to be humble, I don't go around acting like a "know-it-all". Instead, I work it into my story. That is where it will show my knowledge.
Besides studying what is in your story to stay humble, you can also stay humble by attending workshops held by authors, seminars, and reading books on writing. Keep learning your own craft. See what others say about writing and take everything to heart.
There is no shame in learning. There isn't a measure on how much one person can learn in their lifetime. There is no price on learning. There is no price on the person who is humble.