Don’t autohit. This means you should not be writing your attack actually hitting/affecting your opponent. Leave that to them.
Take damage. Even if your character is an INVINCIBLE GOD, it’s no fun if it’s a curb stomp battle. If you have to get creative about the form the damage takes, GOOD. It’ll flex your writing muscles.
DEFEND-DODGE-STRIKE. You can be good at two of the three. Which two depends on the nature of your character and his or her weapons.
Your post should take, essentially, the following format: React to your opponent’s attack. Hit or miss, react. You write their success or failure. Act out your character’s response to this attack. Then, attack your opponent.
Keep your attacks specific without writing what damage it causes. For example, don’t just say, ‘He threw a punch at her.’ Tell your opponent where you’re trying to hit them and how so that they can accurately reply with the way that they deflect, dodge, or get hit by it. Try, “He threw a sharp jab directly at her nose.”
