These days my style is to have a specific character arc in mind, and build off that. In that way I treat my rp characters very much the same as I would a novel character. They have obstacles, wishes, dreams, motivations, goals. Most of that is based off what sort of direction I want to take them and what I'd find fun writing.
I find Plotting to be reasonably simple. Whether original or someone else's idea it doesn't matter to me. I find "organic" writing far more difficult without some kind of direction to know where my characters are heading and why they are on the road to get there in the first place. This has caused me No End of grief because I seem to pick sites that prefer "organic" writing to "plot" driven threads and storylines instead. In my experience the Best sites are the ones that have both Site Driven plots that are welcome to the public, and whatever ones you can personally create for your own characters or those you write with which are generally private.
I am… not really a plotter at all. I am in terms of site-wide plots or planning an adventure but when it comes to interpersonal character-to-character plots I’m not particularly fond of it. I like a more spontaneous approach to most of my threading. Popping two characters together and seeing what happens. Coming up with things on the fly is a lot of fun for me
I thought it would be fun to see how much my preferences have changed since 2021. So, I still prefer to plot with a basic idea or structure for the thread. I enjoy an overall idea like, for example, your character dropped their sketchbook which has some personal sketches and thoughts in it and my character ends up finding it. So, that would be the general set-up of the thread. I can jump into open topics and the like without prior plotting commitment, as that scene is already established. But, when it comes to replying to plotters/shippers, I am 100% going to try and come up with some general idea for the thread, and still do not work all that well with the "Just throw a post up somewhere and I'll reply to it".