As most Internet users are aware, it is harder to convey what you mean in written text such in a PBEM game than when using live, spoken words. Since Play By Email is a form of text based communication, there is a chance the other players will misunderstand your intentions if you are not careful. Keep this in mind when writing your posts.
In a face-to-face situation, you immediately get feedback from the person you are talking to. You see if that person understands what you are trying to say, you get feedback on how much you need to describe and when it is enough. When role-playing your character in a live game, you use your entire body to describe your characters feelings, actions and reactions. You use your voice to do the same when your character is talking “through” you.
Imagine your character saying “Yeah, right” in response to a question or comment from another character. How can you be sure the other players understand that your character just gave an affirmative answer, and was not being sarcastic? “Yeah, right” can mean different things depending on the tone of your voice. This is not a problem in a regular role-playing situation, but in a written context it is harder to make this point. Again, the problem is that written words can not express feelings the same way as spoken words can.
There are a couple of ways you can make sure your readers understand what you mean. The first way I am going to tell you about is the most simple of them. Just tell them what you mean! Why make it harder than it is? “‘Yeah, right”, she said sarcastically.” Explains exactly what you want to express. No more guessing!
Another way is to “write around the problem”. By using other words that better describes what you mean, you get rid of the problem. The downside is that it can be hard to find words that fit the characters.
A third way is to explain the situation in more detail to make it obvious what the character means.
It does not really matter which one you use, or if you perhaps combine them all, the important thing is that you are understood.