As I look back, I recognize three major behaviors I needed to succeed.
Persevere: It's easy to quit. It's harder to keep going especially when rejections fill your in-box. If you persevere, you will improve. Read craft books, books by talented writers, and seek critiques of your work.
Prioritize: Time has a way of sucking you in. For the good and the bad. If you choose to write, then you must make writing a commitment in your life. I tell everyone I work from home every day. That means limited phone calls and that I also schedule my writing time. I take writing seriously as my business. It is no longer a hobby especially when I have an agent waiting for the next book.
Pray: All the time. I pray every day God would guide my writing and that my words might touch one person. I pray He gives me the ideas I need to write and gives me the stamina to finish and not quit.
No one ever said writing is easy. When someone tells me they have always wanted to write a book, I ask, "What's stopping you?"
Add these behaviors to your life and your answer will be "Nothing!"