The main thing I fall back into but try to avoid is splitposting. Like when your characters are having 20 conversations at once somehow, it kind of messed with the flow of time, but actually it was how I first learned to rp. I find an RP is more organic when this is avoided. Its more common in RPs that have high minimum word counts for posts though, I think, which shows sometimes having rules for things like that can impact your output substantially.

Edit: i submitted before I was done

This was out of my comfort zone because it took some pretty big adjustment to start minimising the splitting. I felt guilty any time I didn't reply to certain parts of another person's post (and if i did thoroughly it would split things even MORE). It took me a while to figure out where the line is for me and while some splitposting is just the nature of the beast, I'm far more comfortable than I was about making the call to tighten things up again in my replies.