Some general advice

I'm by no means a particularly good or experienced RPer or GM on this site, but I reckon I've picked up a few things in my time here that I'd like to share. If you're pretty meh about the whole thing, you can stop reading right here.

GM's:

Invite people. It's just better that way. You can create the shiniest RP you've ever made and stuff it full of tasty lore, but if you just sit around waiting and hoping for people to join, well, it might happen but it's still not as effective as just shooting peeps a PM. If they're interested, dialogue can begin and you can help new players get started by letting them know what's going on in the RP at the moment, summarizing past and current events, and suggesting ways they can start off running.

Also be open to suggestions, because that's good as well, but if you know what you want and things don't exactly gel together because of what the player wants, try to find a way to compromise and work things out. Suggest alternatives and the like. Don't be afraid to say no, just no, either. You don't have to be rude about it, but you ought to remember that you're the GM, you're the boss, you say what goes and what doesn't. In other words, don't be a doormat, but don't be a prick either. You're in charge of who you let into your RP anyway.

Use the Character Pool. It is a wonderful feature of this site that probably doesn't get enough love. You can just look around for characters that might look like they could fit into your RP, then have a chat with their owners about it and if it's a go, then it's a go. Simple, easy, breezy, beautiful (what?).

Info dumping. This is of debatable use as while it creates more complexity, it may also decrease depth and by depth I mean all the things about the RP that makes it engaging. This video will explain it better than I can, even though it's mainly about video games, but I reckon it could apply to RPing as well. Anyways, what I'm getting at here is, info dumping could help in that if a player ever needs to know anything, the info is readily available, but if an RP'er needs to know pages and pages of stuff before getting started, you're doing it wrong. It's just going to drive people away which is not good, unless that's what you actually want as a way of filtering players.

RPers:

Check your spelling and grammar, and make sure your posts make sense. That's just the least you can do.

Create interesting characters. I wouldn't consider it a mandatory obligation. A character's personality and whatnot will show through the RP after all, but it's just a good thing to do.

Work with the GM. Don't be afraid to ask questions or make suggestions and compromises, and if ever faced with rejection, for the everloving sake of turtles, don't take it personally. Remember that if you don't like things, you can just leave. No drama, just pack up and go. This is a course of action that will always be available to you. You have as much right as the GM to say no, just no. In a perfect world, there'd be no such conflicts, but let's face it, it can happen sometimes. You just gotta try to be stoic about it and take things with grace.

Now, more on asking questions and talking to the GM's, this is especially important. There's no need to be shy if there's something you don't understand or are just curious about. Chances are, GM's will like, nay, LOVE to provide answers. I know I just get positively giddy when a player in one of my RP's suggests something to add to the world. If it's good, I allow it. If it's not, we talk and come up with something better or just drop the matter and let it die peacefully, no muss, no fuss. So the overall bit of advice here is collaboration. Collaboration is key. If you're not sure of something like how to start out in an RP, again, just talk to the GM. Never doubt the power of PM's (hurr hurr).

UNDERSTAND THE RP YOU'RE JOINING. Again, this means questions, talking and maybe a bit of reading. If you're in there and you're not sure about the plot, the setting, what's going on, etc., you're just going to look like a fool; about as much as the GM who fails to make those sorts of things clear.

Donate characters to the Character Pool. Seriously, it could use a bit of attention.

Be active. It just goes without saying.

~~~

Now to anyone who takes note of all this, whether you agree or disagree, understand that this is simply my own understanding of RPing on this site so far. You may regard or disregard it as well as you like. Please forgive me if anything I've written here has rubbed you the wrong way. That was surely not my intention.