The main difference I find with my RPing is that when I first started (so, late 2008) I would literally just write the post as the words came to me and submit it. It wasn't until I started playing my character Daxton (about mid 2015?) that I got into the habit of writing out a post, hitting preview, reading it, editing it, preview, read, edit, wash, rinse, repeat ad infinitum. I did this because I kind of had to put a lot more thought into the character and the sentence structure I used with him than with any of my previous ones. But then once I got into that habit with him, I ended up doing the same thing with every other character I play because it had made me so aware of how many little mistakes I make when I write, from grammatical errors to phrasing that can be entirely misconstrued.

I don't really know what I prefer; before, I could write out a post quickly and easily and submit it and move on to the next one, so my RPing was a lot faster, but my posts could also end up kind of nonsensical and I now literally get so anxious at the mere idea of posting something I haven't extensively proofread and reworked. Now, I generally prefer the final product of my posts, but the entire process takes a lot longer and it can be a whole Thing™ which can end up overwhelming, and I am always overly critical of myself while I'm writing (which can be a hindrance in RPing as it's really supposed to be for FUN).

I've definitely gotten better at fully reading and processing the posts before me/that I'm responding to before I post, whereas when I look back to my early RPing days my memories all seem so frenzied in my rush to get posts out that I wouldn't fully take in what was going on, and would miss vital parts of other people's posts.

General consistency is another thing. When I started out - and probably actually for quite a while afterwards - I was really not great at being consistent with my characters' lives. I often made a lot of stuff up as I went along, and then completely forgot certain details, or added in quite significant aspects to their lives after I'd been playing a character for a while. When I started RPing my first character (Jake) his bio was the bare minimum in regards to details, and the only place I was documenting anything to do with him was in his RP posts. I know a lot of people RP like that but I do not have a reliable enough memory for it, and ultimately I couldn't keep track of things even though he was the only character I played. These days I love writing character bios, and many of my characters have more than one (generally differing in how much detail is written), so I have something to refer back to and detailed established histories and all that fun helpful stuff.

Nowadays I usually bring the details of the environment into my posts - my character fiddling with the arm of a chair they're sitting in, scuffing the toe of their shoe against the stone floor, loosening their collar because of the stuffiness of the room, noticing and focusing on various trinkets and thingamabobs in their immediate vicinity, hearing a bird squawk outside the window - stuff that brings it back to wherever the RP is taking place. It doesn't really have any effect on the back-and-forth part of an RP, but I like to practice including details like that so I'm in the habit of it when I do other prose writing.

In contrast to my early RPing days, I'm also now in the habit of including ridiculous amounts of character introspection in my posts, which is partly why they can get so long - being concise (as you can see from this post) is not my forte.