Every table top gamer, ever writer, every story teller will have their own opinion and feel of what makes a memorable character, good story, and wonderful experience. Yet, amongst these divergent opinions there are some key tenants that bring together a pleasant and enjoyable ride.
Merely focusing upon table top gaming viewed through my opinion and experience the following are a few important rules to remember to play and run AWESOME;
1 - The game is for EVERYONE to have fun, if you aren't having fun DMing, if you don't like your character, if you aren't having fun, don't just stop and say I don't like this. Take the time to understand why you don't like it and discuss with your group. You may not be the only one with the problem. This leads to 2.
2- The game is a cooperative bit of storytelling everyone involved in the game is responsible for the game being fun. Just because you are a player, does not mean that you're only duty is to roll the dice the DM tells you to. Be a part of the world, make your character stand out, change the world.
3 - DM's, if you want to make the characters do something don't force them, talk to them about it before hand. Tantalize them with story and let them walk into the gates of hell willingly.
4 - Set the scene. If you want a game to be memorable, get a thesaurus and set a creative and drawing description of the scene that draws both player and character into it. The hardest thing to do is to draw emotion from you players. Challenge yourself as a storyteller and try to set scenes that make the players feel.
5 - Make it fun - If the game is nothing but psychodrama, angst, and struggle, your entire group will lose interest fast. Have some lighthearted and fun games alongside your deep story.
6 - Play to the group - If everyone is playing a certain type of character, run for that type of character. Build a character that compliments the group.
7 - Team Building - The ENTIRE group (DM and Players) should be working together to weave an epic tale. This is not a battle between the DM and Players, the players should not be after one another. I am not saying that there should not be character conflicts, just keep the drama in the game and leave it at the table when you go home.