The first and foremost rule of RP combat is to have fun and keep it in character, respect your opponent and she/he will do the same of you.

On God Modding - Good modding is generally defined as making a character with godlike powers or acting like a god. The primary offending aspects of godmodding are refusing to lose a fight or die, and wantonly killing other characters. Its generally considered poor form and inferior playing ot have a charcter which cannot be killed or continually self-ressurects.This may result in a wanring from moderators. The big problem with godmodding however is invincible characters who run around killing, attacking or otherwise harassing other characters. This will not be tolerated and will result in a warning from the admins, repeated offenses with screenshot evidence may result in a temprary ban or deletion of account.

On OOC Harassment - It is permissible for a character to taunt another character any way he or she likes, however Out of character insults whether in an ooc context or not are not acceptable. These include but are not limited to: Verbal bashing, personal threats, racist, sexist, religious bashing etc will not be tolerated. Use your common sense, if you think it might be OOC HArassment it probably is. Repeated harassment will result in a warning and possible deletion of account.

On Random attacks - It is generally considered rude to simply barge into a room in which RP is occuring and attack random players, however since it is in the nature of many characters to do so, it is not against the rules. However if a player does not wish to be involved and tells you such though and OOC comment or whisper, and then either excuses themself to another room or goes temporarily OOC, then you must leave them alone, not doing so will be considered OOC harasment. If your chharcter has a legitmate reason to attack the other character and the charcter does not respond and chooses to go OOC or leave the room, you must either challenge them to a  duel, or simply ignore them yourself, hounding them down repeatedly is considered OOC harassment.

On Duels - A duel is a special kind of fight which can be used to kill a character permenantly (IE have said account deleted, or render that account permenatly OOC). To begin a duel both players must agree to the form of combat beforehand, as well as any conditions (permenant death or crippling etc), these condtions must be told to an admin before the fight begins and also be saved to screenshot. The duel must be witnessed by a witness for both sides. The deathblow (or blow which ends the duel) must be saved on screenshot and sent to the admin once the match is over. The result is that the loser, if killed, will have their account deleted or rendered permenantly OOC, if the player chooses to bring that chharacter IC again, they will be warned and then the account will be deleted.

On fighting in general - A fight generally consists of P1-Action P2-responce,P2-action P1-Responce and so on. However fighting may be carried out in any way you wish, just be sure to agree on a system BEFORE the fight begins. Also it is poor form to continue using a charcter which has been killed in a fight, and is by most considered god-modding. This is not in itself against the rules, unless said character is used continually to harass other players, but will probably result in you being ignored and called a godmodder by other players.

On called hits - A called hit is an attack action in which the attacking player calls the damage without giving the other player a chance to defend, and is considered the poorest of poor form in combat. Keep in mind this does not include striking at a characters weakness or exposed point, that is in th very nature of combat, but rather attacking ant not allowing a defensinve responce action, for example:
"High orc rams his fist into Max Blackblade's stomach so hard that he pukes his guts out onto the floor."
The example above is a called hit and is in fact, a form of god-modding, a good substitude for that would be:
"High orc aims a low left handed punch at Max Blackblade's exposed stomach with enough force to make a man puke his guts onto the floor."
See the difference? just a few words changed and it makes the difference between a called hit an a perfectly legitmate attack. You may not realize this at first, but if you haven't been in a fight before, watch a match or two to get the idea, you'll pick it up fast.

Thats about it for the generall etiquette of combat, once again, unless otherwise stated these arent rules, just suggestions to make the game enjoyable for all. So give it a try and most importantly, have fun.