Guys,
If you want to do a good storyline, the best way to go about it is to write about subjects you know. Or try to base it upon a theme like Sci-Fi, Fantasy, etc...
That would be the best way to go about it. Also, Conner94, with due respect you have a good idea. You do though need to trim down the story line quite a bit and write a storyline about a paragraph long. Good games don't just give a storyline and purpose. Good Games build upon the storyline and drives the purpose. For example, Half Life. Where did these creatures come from, what do they want, why is the army attacking us. Those are the thoughts as they go through a players mind. Those are some of the thoughts you want them to be thinking when they play the game.
SoulMan
This is as backwards as is This