I also use tags with genres. The word, fiction, is eliminated since it just isn't descriptive. However, you can start by separating fiction from non-fiction.
Even though the Men are from Mars... book has been now classified as a work of fiction (authors made up much of it), I would normally classify it as non-fiction. If you have a lot of non-fiction, then put it under self-help.
I put the Sharpe collection by Bernard Cornwell under Adventure. This is one of MY examples of books that I struggled to figure out how to classify. I have very little general fiction that doesn't fit in Adventure, Crime & Thriller, Mystery, Sci FI, Fantasy, Paranormal, Horror, Craft, Western or Cooking so it just lays in the the category of General Fiction. For your "Lovely Bones" perhaps you want a Drama category?
In my Mystery section, I now have so many mysteries that I added a category called Cozy Mystery to differentiate amateur sleuths from professionals primarily because a family member prefers the cozies. Sometimes you just have to combine stuff. I found it impossible to separate crime from thrillers. Since Mom and I are the only ones who read crime and thrillers, it's a nonproblem.
The biggest problem that I have is that when I do a group download of metadata, it always includes all these genres that I don't want to use. I finally figured out how to clear it en masse using Calibre so I don't have to use any bad language.
Consider looking at the metadata to see what categories are used to give you ideas for sorting.
Finally, don't waste your time resorting. Spend it reading. Generally, people reread only a handful to maybe a few hundred books EVER. So, spend your time fixing these up in a personal library rather than trying to endlessly organize a bunch of stuff you may never read.