I personally am godawful at using Artbreeder, and lowkey I don't trust AI, so I usually start with doodling them to get a general gist and/or look around on Pinterest for good vibes. Usually, I find it hard to find people who look exactly like what I'm going for, but Pinterest always helps with hairstyles & outfits.
I also will always and forever vouch for Picrew. It may not be the most accurate tool, but it's a great launch point for figuring out how you want a character to look. A couple of my OCs started as me fooling around on Picrew and now, they're fully-fledged characters!
(Also, from experience, a lot of artists want reference pictures when asking for commissions, so if that's the route you'd want to go, I'd recommend doing something like Picrew first.)