One good way to find the right publisher for your book is to find similar books in your topic area or genre, and submit your manuscript to the publishers of those books.
When using this method, you do need to ensure that a book very similar to yours hasn’t been published very recently. Publishers will often reject books that are too similar to those they are currently trying to promote. You’re looking for books related to yours, but not exactly the same. Books that will have a similar audience.
Yes, that’s very hard to figure out. I never said this was easy.