Role-playing is a lot of fun, but for everyone to enjoy the experience it is important to follow certain guidelines when it comes to etiquette. The most important of these is God-moding, but there are other important considerations as well. Throughout the guide, I will refer to two fictional characters of Goofus and Gallant to use as examples of individuals who do or do not know proper etiquette, though I will also mention players by name where appropriate.
The rules can basically be summed up in two points. Point one is that you don't want to act like you're better than all your comrades. Roleplaying is a cooperative game; the goal is for everyone to win, not just you. Point two is that the point of an RP is not to "win", but rather to put on a good show. Most of these rules serve to allow for appropriate tension and suspense to occur, so that those watching (Including the other RPers) having a gripping moment wondering what will happen next.
God-moding is, as the name suggests, role-playing as if you're playing a god, or someone with cheat codes. God-moders tend to make all the other participants in an RP irrelevant, because they can defeat anything and do anything, all by themselves. This tends to quickly remove any tension, suspense, and excitement from the RP as any conflict that comes up is resolved almost as quickly as it begins.
God-moding is surprisingly difficult to avoid. Even barring the temptation to be strong and "win", you have to tread a fine line where you're useful to the party, but not without leaving them in the dust. There's also the inevitable power creep that happens as one RPs for a long time and picks up alliances and magical items here and there. Probably the best way to avoid this is to start off relatively weak (The abilities you have from your class in-game are a good starting point), and if you get a magical artifact from a quest try to limit how much power it gives, and preferably have a reason to give it up later. This is also where being in good communication with your fellow RPers is good. Ask for feedback, they'll probably tell you if you're starting to become over-powered.
Goofus role-plays as an ancient magical creature with claws that can shear through anything like a hot knife through butter.
Gallant role-plays as a hylian adventurer who gets through adventures with the help of his friends, and rarely comes out of a fight without a scratch.
There is a tendency in RP for folks to try and make their characters overly special. It's closely related to god-moding, except rather than dealing with power it deals with appearance and personality. "Special Snowflakes" tend to be long lost princes of ancient dynasties, tragic outcasts or chosen ones for obscure prophecies. Sometimes it's their race, like half-angels, half-devils (or the ever popular devil/angel hybrid)... actually half-anything usually tends to run into this. In either case, the character feels the need to be more special than everyone else, and it usually winds up looking cliche and raises some serious questions about whether the RPer is compensating for something.
The important thing to remember when role-playing is that normal is good. The audience wants believable characters who they can relate to, even if these characters go on adventurers while they do not. Your fellow RPers want to feel like the RP is fair, and don't want one RPer acting like they're better than everyone else. Making a "special snowflake" bothers both of these groups. When in doubt, stick to the races in-game, and give yourself a humble past.
Goofus role-plays as the long lost half-esper prince of Guardia, with the authority to command anyone and being so tragically misunderstood with his mixed blood
Gallant role-plays as a koopa surgeon on a quest to find the cure to an affliction ailing the Koopa Kingdom.
Interference is something that not every RP community deals with. If people are just randomly RPing for the sake of RPing and there's no clear plot going on, then you can more or less ignore this. Every schedule RP, on the other hand, tends to be run by an individual who is more or less writing the story and deciding where things go. In these circumstances, there is one very important thing to remember:
You are a guest.
When participating in a public RP, you should not attempt to steal the spotlight away from the person running it. If you want to tell your own story, that's all well and good. Don't go crashing someone else's to do so. It's also perfectly fine to be the background character from time to time. You don't always need to be the one who comes up with the answers, defeats the big bad, and saves the day.
As a participant in a scheduled RP, there are many things you can do, but it is NOT your job to dictate where the plot goes. This is where the rule gets tricky. While stealing the spotlight is a bad thing to do, it is likewise bad to just not contribute at all. There is a difference between assisting and driving a plot, and between the main plot and subplots.
Driving a plot is when you control where the plot goes, as well as the speed and any interruptions. Much like driving a vehicle. The person driving a plot determines what the goal is, what and where the objectives are, who the enemies are (and usually controls them), and most importantly is the person in charge of any and all concepts introduced for the sake of the plot. This last case is the most common way in which interference occurs. Let's say Gallant runs an RP, an in it he has crystals that grant magical powers. Goofus manages to get his hands on one during an RP session, and makes up some rules for how they work. In this case, Goofus is altering a concept (the magical gems) that was introduced in Gallant's RP. This is generally not allowed.
However, what if someone wants to borrow the spotlight? What if they want to be an adversary at a certain point, have the RP go to a certain place, or have the introduced concepts do something new? The correct thing to do in this case is ask the driver. Simply have a chat with the person running the RP (Preferably in advance, before the session) and ask if those changes can be made. They can decide whether to allow it or not. Please abide by their decisions.
Now, assisting a plot is generally what you'll do when you join a scheduled RP. In this case you're generally along for the ride, but so long as you're not stepping on the driver's toes you're generally free to do as you wish. A good driver will offer plenty of opportunities for those assisting to do things, such as conversations and combat. There may also be moments where there's a pause in the action where the hero needs something done, like searching a room, busting down a door, constructing a barricade, or other such thing, and this is generally a cue for you to hop in and show your own experience with the problem. Though, even this leaves little for those assisting to do. Here we have the distinction between the main and sub plots.
A main plot is the story the scheduled RP was made to perform. The Mana Spirits RP run by Mogwai, for example, has the main plot concerning finding the mana spirits. Often, figuring out the main plot is easy. If it's not, then the person running the RP is doing something wrong.
A sub plot, on the other hand, is often made by those assisting in an RP and are less obvious. Oftentimes, these plots are the character's reasons for joining the RP. Using the aforementioned Mana Spirits RP, it has subplots of Eevee's romance of a sorts with Mogwai, and Helios looking for mana shards as power sources. In both cases, these are minor plots that serve as their purpose for accompanying Mogwai, and are furthered by their participation in the main quest. Neither directly interfere with the main quest, but rather they serve to flavor it. You can even have your own main plot that you run cameo as a sub plot in someone else's main plot. So long as it doesn't interrupt or alter the main plot, it works.
Some drivers prefer a bit more order to their RP sessions, in the form of turn orders. These are rules to say who can act, and when, and there are three general types seen so far.
In Freeform turn order, everyone is free to act as they please. Generally, this is used for more casual RP sessions, such as when everyone is just talking to each other. It's rarely, if ever, used for combat.
In Turn-based turn order, there is an established turn order. Players may emote on their turn, and at no other time. This is more restrictive, but is helpful during highly technical situations, such as combat, where it's important to know what everyone is doing and where.
Loose Turn-based is a lot like Turn-based, except with the rules slightly relaxed. The person running the RP starts each turn, and every person joining gets one action. This makes sure everyone gets a turn, like Turn-based, with less rule-keeping. It can make for slightly more chaotic combat, however.