What a huge part of my discovery process!
The real heavy hitters for algorithm pick-up seem to be the ones that name a specific feeling or scenario. #BookTokMadeMeBuyIt is obviously the big one—it signals a direct, community-driven action, which TikTok's machine loves. I've watched books blow up from that alone. But also, the hyper-specific mood tags like #DarkAcademia or #CozyFantasy do wonders. They tap into a visual aesthetic and a reader's desired vibe, not just a genre. The algorithm can link that vibe to similar aesthetic videos, creating a powerful cross-recommendation loop.
Don't sleep on the challenge-based ones either, like #TBR or #ReadingSlump. They invite participation and story; you get the 'before and after' or the 'struggle' narrative, which is highly shareable content. My feed is constantly refreshed by people using #SpicyBookTok, which has this hilarious, conspiratorial energy that feels like a secret club. Those niche tags build tighter, more engaged communities that the platform notices and amplifies. My own 'for you' page is basically a curated list from these tags now.