Don'ts:
Vampires
Zombies
Werewolves (not main focus)
More than 5 books in the series (unless it's really really good)
Too much action
Too much romance
Political
Historical fiction
Aliens (unless they look human)
Dos:
Young adult
Love as a side story
Refreshing
I've never read it before
Dystopia
Furturistic
Life after death
Fanstasy
Sad
Unpredictable
Animals (including shapeshifters, selkies, etc.)
Magic (fairies)
Diary-style
Angels
Chick lit (not too cliche)
I'm not too picky lol. Just some things I like and dislike (there are always exceptions tho)