Rituals -- Rites of Passage
But many books have rituals and/or rites of passage. And if you write fantasy, you end up making your own. This falls under the Religion Worldbuilding category. I know some do huge amounts of world building before starting, but I knew I had a Celtic/pagan society in Celta, and a religion based on mysticism and Song in Lladrana.
I don't think I've dealt with a funeral (or memorial service in the case of Lladrana since the fallen warriors sink into the planet Amee). Healing Circles I've done. Banishment. Disinheritance. Wedding. Coming-of-Age (Choosing a Baton -- twice, becoming a Scholar -- journeywoman in Amee Sorcerous Circles). I've referred to many off stage (now that I mention it, including a Celtan funeral).
But I know, in general, what happens during my rituals, have enough underpining of world building that I don't have to research before writing a scene (though I have with Celta rituals).
I've been to a memorial service this year, a non-denominational one for a gay friend. This one will be different. I'll be observing, because writers always do, but I actually think that will be low on my priority list. Time to get moving to get to work early so I can help prepare the "funeral meats."
Oh, and that reminds me that people are VERY touchy about their rituals, how they are done, right or wrong.
So two points -- think how your major rituals would be handled, they should come from the spiritual basis of your culture. Also, conflict could be initiated or aggravated because of a ritual.
May your next ritual in your work fascinate.