Maybe it’s true that you aren’t the best person for the job although someone, somewhere thinks you are good enough. If that’s the case (and is it really so awful?) adopt a mindset that’s about improving and growing, not about getting rid of the voice telling you that you’re a fraud. That voice is probably going to be there to a greater or lesser degree every time you step out of you…
The goal is quantity over quality, but that quantity doesn’t have to come all at once. If you only write 100 words in a sitting but you write every day for a month you will have 3,000 words that you wouldn’t have otherwise. 3,000 words that you can turn into an eBook, a few course lessons, a blog mini-series… you name it!