Meta gaming – Your character isn’t a mindreader
If you’ve not heard of meta-gaming before, it’s a term that exists in all types of roleplaying, especially play-by-post and tabletop D&D type games. Essentially you, the player might know some details that your character might not.
Meta gaming is when you play your character, assuming that s/he knows this information too.
For example your characters are heading into a trap. You know this, because you’ve agreed with the other players that this is what will happen. Your character won’t be aware of this trap, so don’t start making them suddenly overly cautious. Making your character doing anything out of the ordinary in this scenareo like having them check every corner, expecting the trap to be sprung shows that your character knows something they shouldn’t.
Of course if your character is naturally suspicious, that’s fine! But don’t make them act out of character just because you know something they shouldn’t.
Or maybe your character IS a mind reader?! Is that an ability you allow in your game? Because some would say it’s bordering on Godmodding territory (where the character might be too powerful, that it annoys other players), but that’s a decision you have to make with whomever runs your game.
There’s more written about mind-reading & other things that annoy roleplayers in this article written by Misty from Phoenix Roleplaying.