I'd like to begin by stating that this is all in reference to difficult players not difficult characters. Difficult characters are often a great enhancement to roleplaying, and should be dealt with accordingly.
Have you ever been dealing with a player who just doesn't seem to care for the rules? One who just wants to get what they want no matter what you or any around you may be after at the moment? Or perhaps one who just can't take the hint ( Even when that hint is a direct request in an OOC PM )?
Have you ever been involved in an IC fight and the other player simply refuses to play things with even a hint of fairness? Battled a god-moder or other form of power-gaming oppoenent? Or how about being attacked by some random person who just thinks it would be fun to interrupt you because people seem to be talking to everyone else but them?
If you've answered yes to any of these questions, then odds are you've dealt with a difficult player. While not necessarily the worst thing in the world to have to cope with, or the easiest, it is a situation that can be turned around, and I'll see what I can do to help ease this. I'll cover a few of the major types of difficult players and give a few suggestions on how to deal with and help guide them toward the shores of compromise.
Power Gamers and Other Combat Problems
Well, first off, I'd steer you to read both My Combat Guide and Nugan's How Not to be a Power Gamer threads for some ideas aside from what I'll be listing here, as they are both highly informative and worth reading if you haven't done so already.
Second of all, there are powerful characters, and power gamers. That's an important distinction to make, as it can provide great insight on how to best deal with them. If it's a character that throws fireballs around as if they were pebbles in a gravel pit, that's more power-gamey than a character with a short temper that throws a fireball instead of a fist when he gets angry. Conversely, if it's a character who seems to be powerful but seldom uses it to give themself a great advantage is more of a powerful character type than one who acts all-powerful and throws it around in everyones' face. ( Of course these lines can blur between characters, depending on the character's personality. )
Now, if you're dealing with a power gamer, usually the best way to deal with this is to simply take your licks and walk away; let yourself get injured and battered, but just escape when the time is right. This method allows you to get out of the bad situation without getting drawn into the game of who-has-the-bigger-gun where both players wind up seeming to be in a similar light. The disadvantage of this is that the other player might not realize that their power-level is a problem and may very well proceed to get worse. If this isn't good enough for them, and they demand to be allowed to kill your character, then simply be polite and tell them that you don't wish to have your character die. If this still isn't good enough, then walk away and use what means you must. ( Of course, if this goes too far, then use of the /ignore command and/or talking to one of the Magi may be in order, but that should be a last resort action used only in extreme cases. )
An alternative way to get around this is to find intelligent ways for your character to get around the problems. This allows you to show that a character's power is not everything, and that even a 'lesser' character can survive through such things. The drawback to this is that if you do so for too long, you might get labeled a problem yourself for not taking hits. Again, if the player doesn't end his attacking and decide to leave you alone, follow the ascribed method above of leaving and informing them of the problem.
Intrusive Interruptions and other Conversation Problems
Now, there are some players who just don't know when to stop talking or when to leave your character alone. If this is a character trait - that's fine and all the more power to the player for it, but when it becomes an obstacle to the overall roleplaying that is going on, sometimes players have to step into such matters.
These problems can manifest in many ways, persistant interruptions and excessive hounding are the easiest to deal with, usually being solvable by IC means with a quick turn and statement of your wish to be left alone for a moment. Now, there are also the attention seekers who utilize things like yelling, hollering, and other loud, noisy means of getting attention. The best way to cope with these types of interruptions can be to either ignore them until your character is free to react - or until you are willin to react - and deal with them then. Also, you can check out Nugan's Dealing with New Player's if you suspect the disruptive player to be new to the site, his suggestions on dealing with new players are far better than I could provide.
Selfish Players and the I-Don't-Want-To-Give-In Theorem
We all know that there are those players out there who will go to no end to get what they want for their character, even if that means something that both the other players and characters are unwilling to provide. This can be anything from demanding that a character die in combat, demanding that some item to given to them or allowed to be stolen, or any of several other given things.
The key to these situations? Compromise. Try to find as close to a middle ground with them as you can, that way you don't just lay down for them and they don't feel completely rejected from the situation and angered with the site in general. ( Note: I'm not saying that players around here are actually that disillusioned with things, but it is indeed possible. )
By finding a middle ground, the player can become incorporated into a more agreeable form of roleplaying; one that can please both the player and yourself without stepping on anyone's toes too badly. Even though middle grounds are not always easy to reach, it is certainly possible through patience and thought; anything can be possible when we are willing to work together to make the most of our time on the site.
The Direct OOC Connundrum
Of course there are those difficult players out there who just don't know when another player has had enough or is not able to respond to them. These are likely the most difficult to deal with as the problem is much more OOC based than IC based. I myself have been told to 'jump off a cliff' one night while AFK because I didn't reply to a PM, which proves the existance of these individuals. It is seldom easy to deal with these, partly because they are at times just trying to get at your mindset and set you off ( ie, a troll, not the actual creature of course ).
Now, when dealing with these types, the key is to know what you're dealing with, re: whether you have a troll on your hands or a serious player. If it's a troll, the best thing to do is to state calmly that you do not wish to deal with something at this time or in this way or what-have-you, and use the /ignore or reporting systems if it gets to such an extent, though again, such measures should always be last resorts.
If you believe you have a serious player, then talk it out with them if you have the time or the chance, let them know why you aren't going along with their plan or doing what they want or not responding to them. At the very least this will help to cool the coals of any potential conflict and keep things from getting to heated. At the most it will help them to understand the situation and possibly get past any OOC issues they might be taking with the circumstances.
So in short, just keep things peaceful and be patient, even if you get frustrated with something that another player does, try to stay calm and relaxed, it really can help with most things.