I'm sure word has gotten out by now that I'm a text-fighter of no small skill. However, writing a fight scene for an RP is a different animal entirely, and I confess that I have no idea how to go about doing so.

In short, I know how to win against other people, but when I'm writing for pleasure and someone decides to throw down, suddenly I become paralyzed with uncertainty. Among other things, I need help with making sure characters don't turn into Sues for the fight's duration so I can maintain continuity of characters. Similar problems crop up in an RP where my posse is attacked by NPCs, and I have no clue how to go about making it look good because I'm too used to the conventions of PvP (no auto-hitting, etc.)

Could someone give me a hand?

Something that you might use to help you I learned of just today in my Conflict class. It is called the Ladder of Inference and it details the subconscious process based on which we act. You have probably found that in your text combat you never display these steps - you simply act and react. Writing a fight scene is, as you've correctly figured, very different, in that you are not simply trading blows but are trying to convince the audience of the necessity of your actions.

You can use this ladder for various things, but it shines when it comes to making your actions believable. Your opponent has just performed some action, and has likely told the audience the true meaning. A metagamer would misuse that "for-the-audience" information by giving it to his character through no logical means, thus cheapening the fight. Instead, follow the steps of the ladder. Start with what your character perceives of both the environment and the other's actions. Describe it if only to reassure your opponent and the audience that you know what is going on. Then focus on certain aspects, like the last action, and give them meaning from your character's background. Perhaps the sword dance he just watched reminded him of a speed enhancing technique he once saw. Then show the audience that conclusion: your character is now preparing for a flurry of quick attacks. If your post were to follow the ladder of inference, you would have a short scene that is descriptive not only of the current conflict, but also of the character's personality and background.

Of course you can omit steps in your writing which you deem superfluous, or repetitive if you've used a similar facet in a previous post. You also need to hope or inform your opponent that metagaming is out of line in an RP fight scene. However, if you follow the ladder you will create a bundled post which accurately describes a part of the battle. It lets you convey to the audience how your character thinks, and also lets you dissociate your character from your own thought process.

I do need to leave you with a disclaimer: I've never actually tried this. Because I only became familiar with the concept today, I haven't had the chance to test it in an actual RP. Still, I hope you find merit in my theoretical endeavor and give it a whirl - maybe I'm not full of hot air :)