A writer who can't handle editorial criticism doesn't usually last very long. Submit articles to professional gaming magazines like Dragon, Dungeon, Pyramid, or Shadis. If your article is rejected, come up with something else and keep trying. If you learn from your rejections and continue to refine your writing, sooner or later you'll get an article published. Published articles provide you with the start of a portfolio of writing work you can use to get bigger freelance jobs.
Game companies publish writer's guidelines for a reason.
Any writer who can't take the time to read and follow the guidelines probably isn't going to get published. I can't stress enough how important this is. Even if the guidelines mess up your concept, follow them. Some companies don't even accept freelance proposals, so don't waste your time sending them any. Before sending a proposal, send the developer or line editor of the game line a letter outlining your proposal and asking if he or she would be interested in seeing it.