Some ideas that myself and others have used:
- Memories are always fantastic ideas. They allow an incredible level of emotive language to be used, particularly if they are reliving a traumatic experience. They can also be considered both an inner and imaginative journey.
- Comparative experiences between different people, different cultures, different ages etc.
- Make sure your stories show some sort of change, transformation or enlightenment. Teachers wanna see that you understand all that really tacky, irritating crap about "the purpose of taking journeys". Try and write stories that you could analyse in your essays!
- USE YOUR TECHNIQUES! The whole point of creative writing is to not just show that you're inventive and imaginative, but that you also understand the fundamentals of writing so fully that you can do it yourself. Even if it's just your basics: similies, juxtaposition, imagery. More adept writers can start to include symbolism, metaphors, etc. to further their stories. Just remember to SHOW OFF!
A really good story that I used, where I got full marks, involved a grandmother reliving the pain of hearing her parents killed and being captured by Nazi soldiers during World War II. Her granddaughter asks about the tattoo she has on her forearm, which induces an imaginative journey. After remembering her experience as a child, she relates the past situation (genocide of Jews) to the present one, through which her granddaughter is living (racism toward Arabs), and asks whether the world has really changed. Teachers love it when you get all philosophical and start asking questions and stuff.