Grassblades spent a LOT of time being named "Masahiro-verse" (as in main character's name+[uni]verse) while I tinkered with possible titles. I still have the scribbled notes somewhere, page upon page of suggestions and ideas where none of them fit quite right.
My initial instinct is always to go with a longer title with multiple words in it - I like those! - and to stay as far away from the [Noun] of [Noun] and the [Adjective] [Noun]-formats (you know, the "Throne of Shadows", "King of Bones" and "The Golden Sword" kind of titles), as the latter is so common in fantasy novels, which I've read a metric ton of. I find those titles boring.
I started getting a bit closer to where I wanted to be when I remembered that I always liked the titles of Lian Hearn's Tales of the Otori-novels - specifically Grass for His Pillow - and Kim Stanley Robinson's Years of Rice and Salt. I wanted something that felt similar to that, but at the same time, it needed to fit the story and not give the whole thing away from the start.
So after MUCH tinkering and changing my mind, I finally settled on "Grassblades", because it reminded me a bit of Grass for His Pillow which is a lovely title - and partly because the "blades" bit of the title is a wink to the fact that Masahiro's got a sword. XD