I'd recommend getting your full story planned out - maybe even writing a few scenes. Make sure your idea has been developed into a concept.
I also massively recommend that if you can't get an artist to make it into a comic try writing it as a novel. Prose can go a long, long way. You could even adapt it into comic form later down the line.
Make sure that when you're seeking help for a project you give an idea of what kind of work you're looking for, maybe offer some kind of revenue split scheme if you can't pay up front... And give some kind of summary of what you're creating so that you can get the artist interested.