Trust your self.
There are no guarantees with creative or entrepreneurial work. We can never predict the outcome of a creative or entrepreneurial endeavour. Rather, if we can predict the outcome with certainty, then it can be said that the work was not creative to begin with.
Instead, what we have, as creatives, is the practice. When we commit to our practice as a professional, we don't obsess over the outcomes. We follow the process and refine it and learn from it. The outcomes take care of themselves.
When in doubt, all we can do is trust our self. When in doubt, all we can do is show up and do the work.
HT to Seth Godin for writing the book that teaches how to build The Practice.