This validation checklist is loosely modeled off of Brian Balfour's Four Fits, which I highly recommend reading about.
It's also modeled off of my [Courtland's] personal goals. Some of them may be goals you share (e.g. build a company that can be self-sustaining), but others may not, so make sure to tune it to your liking.
To use this list, simply check your business ideas against the various questions and evaluate how they perform compared to each other. It's also a good way to tweak your business ideas to make them better.
(Note that a "product idea" is not the same as a "business idea." A product is just one small part of a business. So if your ideas are only for products, they'll likely score poorly on this list.)