How are you keeping AI-generated visuals consistent across a product?

I keep running into the same issue across the apps I built: AI makes great one-off images, but when I try to generate a set (icons + graphics + launch assets), the style drifts and everything looks like it came from different designers.

For people shipping products:

• What actually works for keeping a consistent visual style?

• Do you rely on a brand kit, reference images, strict constraints, or manual cleanup?

• Any tools or workflows you’d recommend?

If you’re willing, share a quick example of what you tried and what failed. I'd love to learn from real launches.