Ask HN: Where do I turn for help developing an invention?

I've had a few ideas over the years for various household gadgets that I think might have had real marketability. The problem is, I'm not an engineer and I have no idea where to turn for help developing my ideas. I would just take the first step of submitting a patent application, but I suspect that my amateur drawings would in themselves be grounds to reject the application.

I know that organizations that market services for inventors are, by and large, scams, and I don't know any friendly engineers who might lend a hand. So, any advice would be appreciated.