Start reading: when I am looking for something new to read, I usually search by genre; fantasy, adventure, supernatural, genderbender. Sometimes scifi or by a specific tag. I filter the results by descending wordcount. Getting to the synopsis, there is not a whole lot that will refuse my interest. However, if I think the MC might not respect consent I will not read. Additionally, if the cover page has at least one lady (and no dudes) but the MC is male, I will not read. I do not care how much I might like your story, but I will not accept being disrespected by clickbait like that.
Keep reading: There needs to be good filler. Whether it is humor, exploration, flirting, or even that classic low-bar of campfire cooking, I need something to break up the flow a little. If the story is just plot plot plot without rest, I start feeling like I am reading a corporate cash-flow statement instead of something that should be fun.
Stop reading: Several things can make me drop a story. Most commonly, the MC drops across the moral event horizon. As someone who prefers a classically heroic MC, I can't like someone who kills an opponent they could easily incapacitate non-lethally just because "its annoying to tie them up and drag them back to town," and I do not enjoy reading more about them. This just keeps happening with a lot of stories, and somehow I always feel betrayed when the MC is revealed to have always been willing to resort to murder and enslavement.
Next, if the MC is just living through constant tragedy without any rest or comfort, it becomes too depressing to read. Comic relief is important you know! Yes, there's this "rule of shoujo manga" that a FMC is only allowed to be happy for two chapters at a time unless the third is the epilogue. I certainly know it really is the author's job to throw conflict at the protag. But the MC still needs to have their little happy moments in between those unlucky plotlines. I would point to "Karin" aka "Chibi Vampire" (manga version) as a masterful balancing act, with the titular Karin facing really tragic events interspersed with sweet moments with her love interest, and security with her very powerful and aggressively protective vampire family. The constant tension there really made the conclusion emotionally impactful, and I was sobbing for her wedding. But there was also enough sugar and nice for that whole pile of spice.
Stopped reading "Monster Girls Book 1: A Tale of Tails!": So I read this one up to about ch10 or 15 back in 2023 when it was still named something like "KuliKuli the Nekomata," and I figure this is the one you are especially interested in hearing about. In this story, I had trouble understanding the setting. It felt like there was background information the reader was assumed to know about how this world functions, that could have been found in a different work. Maybe "Monster Girl Encyclopedia"? A prequel you wrote somewhere else? So the MC, male (only partly? not for long? falling in love and/or having a romp with Kulikuli seemed to be transforming him somehow, but this was still unclear to me. It felt like I was expected to have already known what consequences a Monstergirl lover would have on the MC's life). Anyway, he had walked over some random dust pile that was actually poison/monster girl repellent? Why are there piles of poisonpowder just sitting in the middle of the road? If it was only supposed to effect Monstergirls, why did it almost kill the MC? I know infodumps are a bad idea, but so are info-embargoes. None of these plot points were properly explained, so I lost interest in a setting I could not understand. Frankly, I do enjoy the slice of life aspects, and the furry soft tails. I was more or less waiting for a round of editing to clear up some of the obscured setting in the early chapters before trying to binge that wonderful pile of more experienced writing I anticipate is hiding behind it.