One complaint I've heard about the Nancy Drew Files series is that the titles are awful. They're all generic titles with dramatic words like "sabotage", "murder", "danger" or "death". Off the top of my head, I couldn't tell you the difference between "Deep Secrets" and "Buried Secrets".
Occasionally, you have a title that kind of describes the book. For example, "Stay Tuned for Danger" takes place on a TV show, and "Two Points to Murder" is about a basketball mystery. You can kind of recognize the book by its title that way. The titles are definitely not as on the nose as "Soap Opera Sabotage" or "College Basketball Murder".
The Boxcar Children series is the one with straightforward titles. Each title is basically "The [Location] Mystery". You can instantly know where those books take place. Occasionally, they have mysteries named after a certain thing, like "The Mystery of the Locked Safe".
Animorphs and Sweet Valley High both have one-word book titles, which worked well for the start of the series. Then, around Book 30, they ran out of good titles. For example, "The Deception". That works for multiple books! But it was already used, and they couldn't reuse it. The later books had to pick less descriptive titles (or just use a thesaurus!).
The Baby-Sitters Club always puts the narrator's name in each title. That seemed to work fine, although with some books, the narrator's name seemed to be an afterthought, like "Little Miss Stoneybrook...And Dawn". The California Diaries spinoff didn't even bother with titles, really. Every title is "[Narrator] Diary [Number]," like "Ducky Book Two" and "Maggie Book Four". I'm sure that when I read these books, I'll have a hard time keeping them straight.