It's easy to expend a lot of Energy worrying about whether what you're working on will be a success.
I've done it and I'm sure I'll do it again, but it's wasted energy. It can even lead to writer's block.
In his book, Drawing From Within, artist Nick Meglin writes:
"I once asked a writer friend what he was working on and he said wryly, 'I'm Writing a hit play.' He knows what all playwrights know: You can't write a hit.
You can only write a play and have it performed. The public will then determine if it's a hit.
Neil Simon wrote more commercial hits than any other living playwright, but even he would be the first to tell you he never knew which of his plays would be a 'hit.' It's totally out of his control. What he does control is the time and energy he devotes, and the personal statement he makes in his writing. When he writes 'The End,' the curtain goes down on both his play and his control of its success."
That's worth repeating: The only thing we control is the time and energy we devote to our writing and the personal statement we make with it. If we find ourselves fretting over whether the world will judge our writing to be any good, that's a cue to focus on those three elements instead.