1) How well have your short stories and novels done? If you've got a decent track record with them, you could use those as experience toward writing positions. Just a warning ahead of time: You'd more than likely be writing other people's stories and lore, not your own. If that's not what you are looking to do, then the best bet is to identify what part of game design you are most interested in (modeling, world/level building, programming, etc) and take course that lean in that direction.
2) To say that ideas are a dime a dozen would be to over-value them. Game developers are looking for people what can execute the ideas and turn them into a reality. More importantly, turn them into a fun and engaging reality.