Don't Insult The Moderators
They are there to help you. If you ask for their help they are going to give it to you and some are more honest than others. These games are about the writing and as a writer you need to develop a thick skin. Moderators/Owners are basically the gods and goddesses of the game and they get to decide your future in that game so it is best to try to keep on their good sides. They also might be the one in charge of another game you wish to play in. Making enemies would not be in your best interests.
No Fighting on the Lists
If you have a disagreement with someone on the list email the moderator personally about it or email the person privately about it off the list. There is no reason for everyone on the list to be forced to endure an argument between players.
Some games are intended for all audiences, some games allow more mature and adult themes. Depending on what you are looking for, you should check with the owner/moderator and see what they allow in the game you are looking at.
Some games require audition posts. More games seem to be first come first serve since it can be difficult to find players but sometimes you will have to write an initial post and submit it for consideration.
If you are just joining a game it is a nice gesture to email the owner or list to let them know you are alive. If you are leaving and an active player, or have requested a character it is nice to let them know that you are leaving so that they can open up your characters right away as opposed to finding out a month later after checking the members list and finding you gone.
Many times a game will have a maximum number of characters that you are allowed to have. For example two major characters and three minors and unlimited Made-Ups. Or perhaps two characters total. It all depends on the game and the owner. But it is often best to know your own limitations, what you can and cannot keep up with.
Many games will have a rule that requires at least a post a week or every two weeks or the like. Some enforce it, some don't but it is important not to hold up the game. If you have been tagged and just don't respond it may become necessary for the owner to give you a warning depending on how forgiving they are or they might just take your character away or even boot you from the game.
Lurking is when you join a game but do not post. Or you claim a character and don't post for them. Sometimes owners don't mind if people just read along but other times they do. You should make sure that the owner doesn't mind lurkers because you may find yourself without a character and kicked out of the game. Claiming a character and not posting for them is unfair to the other players. If you don't plan to post for them or find yourself too busy you should probably give that particular character up especially if you are controlling more than one or someone is waiting for that character to become available.
Again, keep the character true to the personality that they were given either by you or by the person that created them. Try to get into their head and write how they would think.
Criticism and On List Comments
Please keep all criticism constructive. Everyone is always looking to make their posts better or help with their characters. If you have something specific to say you should email the writer off the list unless it pertains to a number of people. Singling people out on a list can make them feel attacked and might take your criticism personally instead of accepting it constructively. Please also keep in mind when giving criticism to address it to the specific post and not the person directly. You are discussing their writing, not their personality. Being mean is not a way to get your point across either.
Pay attention to where your character is. If you character lives in Mexico and they are going to visit their friend in LA you can't just warp them there and not take into account the time differences and the travel time length. This may result in you not being able to post for a while, depending on how often people post and how much time passes in each post, but to keep the realism, you might be stuck waiting for your character to arrive in their destination.
Another thing that falls under this category is somewhat a result of mind reading. For example, perhaps character A is dating character B. Character B decides to cheat on character A with character C. Character A's player reads the post about the cheating significant other and suddenly gets this urge to go check up on them. While sometimes scenarios like this can be worked into the game it can take all the fun out of the game for other people who are trying to create some scandal.
Just because someone writes something in a characters thoughts which makes it common knowledge to all the players, it does not in any way mean that the other characters know that.
Separating Game Conflict from Player Conflict
If you have a problem with another player, don't take it out on their characters with your characters. On the other hand some characters are more aggressive and confrontational than others and instigating fights and being mean and rude is just part of their character. Please don't take it personally. If you feel like they are trying to attack you talk to them about it first or talk to the games moderator/owner if you don't feel comfortable talking directly to the person.