So, here’s my advice. I’d like to say that I’m a paragon who exemplifies these points, but—alas—I am not. Do what I say, not what I do. ☺
Avoid over-analysis—especially during character creation. I’m a big fan of over-analysis, but I’m also a big fan of experiments. Often it’s better to just make a choice, play, accumulate data, and save the analysis for later. What’s the worst that could happen?
Don’t look to the rules for options. You know whenever you find yourself screaming at a fictional character for not doing what you would do? You know whenever you’re playing a game and you think, “I wish I could...” Well, RPGs are the chance to do those things. Look for options in the game-world.
Ask questions. Then ask more questions. The GM is your character’s senses. To some extent they are also your character’s knowledge of the world. They can’t volunteer every detail that your character sees, hears, smells, and knows. Plus, they’re mainly using words to communicate all these things to you, which is error-prone. You have to ask about what you want to know more about and to clarify things. Don’t take any action until you’ve gathered information beyond what the GM has volunteered.
Tell the GM your intent. If you try to describe the things you want your character to do in discrete steps, it’s going to take a lot of time and increase the chance of miscommunication. Instead, tell the GM your intent and then describe discreet steps as necessary to clarify.
After you tell the GM your intent, tell them why you should succeed. Look at your character sheet and mention anything that might be a factor. Mention aspects of your character that aren’t on the sheet that might be a factor. Mention things about the situation that might be a factor. Don’t be a jerk about it. It isn’t about convincing them so much as reminding them about things that they might not think of.
Give the GM the benefit of the doubt. It is a hard job, and they’re only human. If you think you can do a better job, most GMs will be happy for the chance to be a player.
Take turns. After you’ve had a “turn”, sit back and let everyone else have a turn. While other players have the GM’s attention, have a pencil and paper handy to jot down notes for things you might want to ask about or do when it is your turn again. Before taking another turn, ask any players who haven’t had a turn since your last one if they want to do anything.
Enjoy your friends’ successes. Even in competitive games, you can enjoy a friend’s success. Make sure you take them time not only to give other people their turn but to enjoy being in the audience.
Cöoperate, involve others, and form consensus. RPGs aren’t always cöoperative, but not being cöoperative is easy. Getting everyone working together can take effort. When appropriate, make the effort.
Take responsibility for your own fun. I’m tempted to leave “for your own fun” off of that. Taking responsibility could take many forms. I guess you should just ask yourself “What can I do to make this game better?”
Give the GM feedback. Before, after, and between sessions, let the GM know what you’re enjoying. Tell them about the things you don’t enjoy too. Don’t expect that things you don’t enjoy will go away, but it is useful for the GM to know the players’ perspectives.
I looked at a bunch of other lists like this. I disagreed with the majority of most of them. So, perhaps the best advice would be to try to figure out what works for your group.