>>13204 (OP)
Not much ritual, but I always keep a pen and paper on me and try to take notes whenever a phrase comes to mind or I notice something striking, which requires (or at least benefits from) taking on a certain kind of perceptiveness to the world. I find it helps to think a lot on what I want to write about, or really what I want to accomplish with it, how it should feel, etc., so the essentials of the piece or idea are bouncing around my head all the time and I can connect what's around me to them. Sometimes I might write down a phrase I have connected to an idea, but it's only months after that it'll come together into something complete, where I've assembled all the pieces mentally (or on scrap paper) to put it together. Sometimes it's outline-esque, or a list of things to include or accomplish in stages. Then it's like a jigsaw on the table in front of me.
In the past I've tended not to write full drafts until I've reached a sort of "a-ha" threshold, but sometimes a draft simply reveals that I don't have all the pieces, and the gaps stand out. Those drafts I tend to toss away rather than explicitly refine.
All of the above is mostly with respect to short fiction, like sub-1000 words. I don't write poems that long, but I similarly jot things down or bash out a poem if something comes to mind while I'm out. And I've also been keeping an overarching idea in my head lately to centre my poetry a bit, which has been helping; even if I'm writing about somewhat disparate things in each poem, it gives an aim or direction of how to approach them emotionally (in this case).
The closest I come to ritual is keeping a diary. I write daily, but without much aim. I write what I do and what comes to mind. Some entries are short, some are long, but they're generally written over the course of a day since I write it on my computer and I'm there most of the time unless I'm out. I think keeping a regular diary was the biggest thing that pushed me towards "writing" more seriously, since it became a regular written form of introspection. At some point I was writing and what I wanted to write was more than just a diary entry.