> 1) Who are the first people you seek feedback from on an idea?
Basically, anyone who'd listen, but the most informative and important feedback always comes from potential clients, particularly potential early adopters.
> Where do you find them?
Now that is the million (or rather billion) dollar question. The answers vary greatly depending on the product and the target market/segment. You have to know your market in order to succeed, and this question is the most important one that tells you whether you know the market or not.
2) How do you make ends meet while bootstrapping? Have you taken part-time jobs like driving for Uber?
There are several ways to make it work. Here's one method I'm using right now:
I got a part-time job cleaning apartment buildings, 2 full days per week, mostly for the physical exercise and a way not to burn out programming. The fact that it makes me enough money to pay rent is a nice bonus. I prefer to think of it as a gym that PAYS ME rather than the other way around.
> 3) (and this is relevant for anyone -- founders or advisors or engineers) Would you consider driving a stranger to the airport in exchange for getting 15-20 minutes of their genuine feedback?
In my case, it's probably irrelevant, since I don't have a car, and prefer to drive as little as possible due to poor eyesight. But in theory, sounds intriguing, assuming there is at least a considerable chance that such a person would be a prospective client (within the targeted market segment). Otherwise, it's probably not worth my time. Also, the feedback process has to be simple and mobile-friendly, in particular one that doesn't create much distraction (that would be unsafe), and doesn't require heavy use of the Internet or devices that cannot be used in a car (e.g. training equipment). The thing is that I'm mostly interested in practical feedback to using my apps/websites, and the feedback should be more than verbal, i.e. I want to watch the user actually using my software - that would give me more information than words can describe. If all I can do is to describe my idea and listen to an improvised opinion, then it's not worth my time either, unless that person is a world-class expert on the subject, but even then it's of limited use (I don't care much about expert opinions, to be honest).