The following are some tips from Aluim and myself. We will add to this list as time goes on. Post any questions or tips you may have about Roleplaying.
No modern slang
Anything that your character says comes out exactly how it says. e.g. afk sounds like ‘afk’ and not ‘away from keyboard’. If you want to sound like you’re sneezing then that is fine. Same with lol, brb, wtf, omg, ttyl, etc, etc…
Instead of using the smiley faces, emote *smiles*, *grins*, or *sneers*… be creative with your emotes so you are not always doing the same thing over and over.
Have an idea of what kind of character your person is. For example, rude, civil, insane (e.g. Wolf), paranoid, etc.
Think about the environment. For example, *shivers* on ice island.