A bit of tough love for 2020, based on some of the problems and challenges I've seen raised here. And all of which I've fallen for myself, at various times:
1 // Not all ideas are equally easy to bootstrap or make a living from. Some unavoidably require eventual funding, so "bootstrapping" is really just cross-subsidizing it with your savings/job until you can get a bit of funding and go a more traditional startup route. Others can't be monetized early (or enough), and are really just a multi-year hobby which might someday evolve. If you want quick, profitable bootstrapping, then rigorous idea selection is your single most powerful tool. Beware committing to the first idea you happen to fall in love with. No idea is good or bad in a vacuum -- it can only good or bad for you and your goals, right now.
(I'm not saying either of these are strictly doomed — and you can certainly find successful examples of both — but they're definitely going to require a longer, harder, and more expensive journey than the typical IndieHackers success story.)
2 // If you're spending all your time and energy worrying about tactical marketing while you still have less-than-stellar retention, zero evangelical recommendations from users, and no deeply engaged users, then you are probably worrying about the wrong thing. It's unlikely that clever marketing can pull you out of the mud, whereas a better product or a more important problem certainly might. Note that this only applies to tactical pursuits (e.g. affiliate, SEO, influencers, social media, partnerships, cold emails, etc etc). Stuff like good copywriting, on the other hand, is essential for new users to understand what's happening and needs to be done early.
(A notable exception to the above guideline includes any marketing activity which builds a long-term asset like a mailing list, blog subscribers, active community, or deep personal network, since that's a lifelong asset which will help all future projects.)
3 // If you personally know zero of your potential customers or need to ask how to find a single conversation or user, you're in big trouble and probably need to find a way to get in contact with real customers (in real life) in order to build the baseline understanding and empathy to start making reasonable product and copy decisions. If you can't find a single friend or have a single coffee with someone similar to your customers, how in the world are you going to build a product they adore and find a way to reach them at scale? It's straightforward to resolve though: either go meet some people or switch customer segments to someone you actually enjoy hanging out with.
(An exception to the above is when you already do know them but are either unaware of how to use an extended personal network or are too shy to reach out to folks. Fortunately, both of these problems are quick fixes once you identify them.)
4 // The previous problem (not knowing any customers) leads folks to send out cold emails to strangers. And those emails don't work very well, since they never do, and then the person goes on IH and asks completely the wrong question. They should be asking how to fix either their (1) idea selection or (2) connectedness to customers. But instead, they ask how to write better cold emails. This is incredibly backwards, and is an example of the common problem of trying to be "efficient" too early. We know that customers come from sales, so we are hugely tempted to skip ahead to just giving the sales pitch via cold emails. But this sort of outreach doesn't work and acts as a subtle sort of busywork which consumes all their time without allowing for actual progress. A similar thing thing happens when folks want to go through the motions of learning from customers without actually having to do the uncomfortable work of talking to a human. So they send out a big survey, wasting a bunch of time to learn superficialities at scale. In my experience, I'd always rather have two actual conversations over two thousand survey results. These sorts of false grabs at "efficiency" are like building your house on a foundation of sand.
(This issue is tougher to identify and debug since it manifests in so many forms. In general though, I'd follow Steven Pressfield's advice that whenever something makes you so nervous that you're finding every excuse and workaround to avoid it, you should recognize that discomfort as your soul's way of telling you that you really need to just go ahead and get it done the hard way.)
5 // Lastly, when you start attempting some of these new soft skills (and stuff like idea selection which lacks immediate feedback), you're going to screw them up. That's fine. Would you expect to learn a new language without hitting any compiler errors? Could you learn to skateboard without falling on your ass? If you flee forever when it first goes wrong, then you'll permanently have that gap in your skillset, making your indie career far harder than it needs to be.
In any case, good luck and best wishes.