Who. Honestly this is super duper important. If you're using multiple characters at once in one reply, you should probably use their names. Who's talking and to whom? Who is doing X action? Etc etc, and so on and so forth, et al... you get the point.

What. This is also important. What is usually used to describe objects or actions, feelings, sights, and sounds. What is X person doing? What are they thinking, seeing, feeling?

When. Used to describe a time period, when is usually a good thing to note. In my Harry Potter roleplay, I try very hard to make sure people know when in the roleplay we are. If I skip a month or two ahead, I usually post it in the next chapter where the skip takes place.

Where. Like realtors tend to say "Location, location, location!" And they're honestly not wrong. Location is everything. If John Doe is in two places at once, usually that's weird but it can happen especially if you haven't yet finished the chain you started in Location X and have started another one in Location Y. Might get slightly confusing but ultimately things will even out.

Why.

How.