This is just my opinion, but I see a lot of "writer looking for artist" posts on this forum from people who just have ideas, a very short and vague pitch, and that's it. Ideas come and go. And as someone with a constant list of ideas who can also draw, there's no appeal, for me, to seek out someone else who just has an idea, and not a script.
When seeking out a collaborator, you're going to need to build a certain amount of professionalism and trust to let this other person, who is giving you their time and skill (often for free), you're serious about your project.
Finish the story before you seek out a collaborator. Make sure it's something you're passionate about, that you want to see come to light, and not just another idea out of a dozen you pick up and put down over time. Again, just my opinion!