There are different ways to look at doubt. The word itself means both “hesitation” and “misgivings.”
Hesitation can stall you, and misgivings can save you. Neither is necessarily a bad thing.
Trusting the voice of doubt is not only a writing rule, for me, it’s a life rule. Many times my instincts have made me doubt, and hesitate, and never once did it turn out badly that I did. The good things always remained a viable option while the not-so-good for me things faded away, untouched.
If you’re an aspiring writing, not every option available to you is good for you. Remember, in the writing world, good for you is good for your career, and bad for you is bad for your career. You may try and fool yourself the two are separate, but they are not.
So listen to your instincts when you have doubts. In this business, it can save you a lot of heartache.