Make sure you use proper grammar and spelling. That alone can make a story about 10 times better. Other than that, don't stick entirely to the plot of the game. There's nothing wrong with starting it out that way, but then having it diverge, because, let's be honest, most of us here probably know the plot of the game by now.

Plenty of pvp ones. Expanded universe stories would add to this. Maybe bungie could use them to add more missions. Such as following paths of the missing guardians.

Ah I see. And question 2? Or is that a secret?