I really don't.
I have self-published seven books on Amazon, and now one novella, and I remain utterly obscure with no steady reader base. Back in the day I tried Goodreads ads and Goodreads giveaways and Facebook ads and Amazon ads and a book blog tour service and getting directly in touch with bloggers and KDP free promotions...
None of it ever made any difference, even though clearly sometimes it does or else these services wouldn't exist.
This spring I opted to finally sign up with a newsletter service, then published my fantasy novella in the summer, in the hope that it would earn me the beginnings of a reader base in time for my upcoming sci-fi release. It didn't earn me a single subscription, even though a free promotion earned me well over a thousand downloads. I did what I felt was fairly exhaustive research on how to properly do an Amazon ad campaign: It got me loads of views but no purchases. Just yet more money out the window.
I did shop around for book bloggers, and actually got in touch with two who were willing to give the novella a review, but it turns out they won't get around to it. Let me be clear: I'm not being angry with them. I understand that book bloggers have an endless flood of material to cover.
Currently I'm still sitting on my next manuscript and I just got in touch with a service that will hopefully get me a pretty nifty cover for 150 dollars. There is nothing stopping me from just releasing it in November, announcing the fact on a couple of subreddits, and leaving it at that. Honestly, I'm much more tempted to just do that rather than spend six months between announcement and release on remedies that experience tell me just don't work.
I don't despair over my writing career as I used to, since pure blind luck landed me that upcoming release in Romania. But it's all a very slow process and I fully expect the process of getting into other European countries to be at least as slow.
Look, I'm sorry for rant-whining, but it gets really hard to feel like even bothering to try.