I play by my own house rules, in where I only control my characters and NPCs. If I needed to control another person's character, I'd ask for permission. I'm used to playing turn-based tabletop RPGs, so Wushu was a bit difficult for me to get used to. After that, I started using some of its rules for other RPs. I'm planning to introduce scab rolls into the Pokemon RP.
If you're confused as to how to participate in other RPs, bring some Wushu in. Play by rules that you're comfortable with. Watch how everyone else plays and model your turns after them. As for story, the only real pertinent information is what happened on that page. If you want to refer to something else that happened before, go for it. But all you really need to know are the turns that happened just before you jump in.
And speaking of jumping in... Wait for a period of downtime. That's usually a good spot to start.