How do I write a good children's novel?

I want to write a children's novel that adults can enjoy as well. One that is essentially a dark literary fiction novel, kind of like one by Dostoyevsky, but for children. What kinds of books should I read? What should and shouldn't I do? Pic related because he was a major inspiration and I loved his books as a kid for doing something a bit similar.

I hope this will be a good thread. Isn't it more of a question of language than of content? Sticking to simple grammatical structures, describing things in a manner that caters to the imaginative mind of a child, using simple words but introducing less common ones that you would like children to know, that would perhaps "blow their minds" upon learning what they are?

Go read the The Worst Witch series and copy the prose. Write about what would excite you if you were a kid.

I hope this will be a good thread as well.

His vocabulary was one of the things that made me love his works so much. I should try being imaginative, without having the ideas come off as infantilising to older readers.

Though content should be important as well, right? What "mature" content would count as acceptable or unacceptable for children these days? Which ones would grasp the attention of children? His children's novels were still very dark in tone, themes, and humor, so I should also know when I'd be getting too dark, right?

One mature that children can handle better than we would usually think, I would say, is death. Poverty is also a great dark topic for children. Or loneliness.

True. I was pretty lonely when I was a child. I'll give it a shot. My only concern is that it'll be considered "too dark" for kids.

Children's literature is too positive and whimpy these days. Parents are generally over-protective (at least parents from social classes where children actually read books), so just think about what a child should read to become a fully realised adult, not what parents would rather buy.

Yeah, exactly. That is my main issue. My concern isn't that I'll write something so dark it'll scare children, my main concern is that parents and other such figures will think that of my books.

You should really read Mark Twain's Mysterious a Stranger, exactly what you are describing

It shows what Children's literature can do

what kind of children's books do you like OP? the first books that came to my mind were Narnia and Harry Potter, although if you say dark, I would think Lemony Snicket's books. and all of these books contain some element of death yet also very whimsical aspects that appeal to children. so I don't think it's a content problem but how you go about describing the situation