These are the game principles from Trophy Gold. Applies to OSR in general too.
Player Principles
Be curious. Both as a player and as the character you are playing, you are an explorer. Ask questions of the gm as well as your fellow players. Probe your surroundings: open doors, look behind statues, shine a torch down the dark hallway. Pay attention to the details you’re given.
Play to win. Play like your life depends on it, because in this game, it likely does. Use your wits, and when you have to fight, fight dirty.
Play to lose. At some point, your luck will run out. Embrace it and lean into it.
Gm Principles
Play to find out what happens. Even if you sit down with a pre-written incursion or adventure module, go into the game with a willingness to let the session unfold on its own terms.
Make the world and everyone in it seem real. Describe the world in sensory-rich detail. The people and monstrosities that inhabit it should have tangible goals and memorable traits.
Be a fan of the characters. This doesn’t mean “let them win.” It means “give them challenges that make you root for them.”
Value player skill over character ability. The characters are purposefully thin. The players should make them feel real, including their own wits and clever solutions.
Sometimes, disclaim decision-making. You are co-creating the story with your players. Let them chime in to flesh out the world, describe things they see, and get invested in what’s happening. Also, when you don’t have an answer, leave things to fate and let the dice decide.
Provide problems without obvious solutions. You don’t need to have all the answers. Give the players lots of chances to be creative, and then reward their creativity.
Ask leading questions and build on the answers. Make players co-creators of the world to get them invested in it. Ask them about their characters, the things they know and observe. Make them complicit in their own fate.
When there’s no rule, apply consistent rulings. This game doesn’t have many rules. If you need to make a rule up on the spot, do so, then be fair by using that rule in all similar situations.