Key Indicators of a valid idea

Just brainstormed this coming up with a new idea, but looking back at the many I had that failed, I think I might be onto something.

1. WHERE are your customers

Not only do you have to know WHO your target audience is, but WHERE they are as well.

If your product is targeting Flutter developers, but you have no idea how and where to find them, you're marketing will be like running up a wall at a 90 degree angle.

2. Difficulty of finding first customer

The second key indicator of a (in my mind) easily validate-able idea is how easy is it to get your product in the hands of a single prospective customer.

If you can find one customer, you can find all of them.

And if it's easy, you have an endless stream of sales leads.

Let's say I'm selling digital tip jars. I can literally grab the prototype and walk to the bakery downstairs to show them the product.

Yes, this is easy for physical products, but if you already know WHERE your targets hangout, how difficult is it to reach them? Are peoples emails public for cold emailing? Do they all have open DMs?

If your main customer is government or construction, those are going to be highly nepotism-based business. So unless you have a huge marketing budget, endless runway or an A++ network, you might be better pursuing something different.

BONUS

The UNIX philosophy:

Do one thing and do it well.

If your idea / product is trying to do everything, it will do nothing extraordinarily well.

Focus on one key function and do it better than everyone else (e.g. Google was just a search engine when it started)