It's a book I read when I was a child so I assume it was a children's book (though I'm not certain). EDIT Mostly likely read post 2000, though published date unknown.
The protagonist was male from what I remember from the story and was suffering (maybe from a missing sibling/something family related).
EDIT the protagonist was not an adult, I think he was teenage age.
The main point of the book I remember was something about following a number of steps (maybe 8?) to hell. Following them/saying the steps would lead you to some sort of monster/devil.
I think the steps were in some sort of rhyme - maybe with the lines "step on a crack, break your mother's back", and "no turning back".
The cover was dark coloured I think (red, black, grey).