Is there a particular expectation in terms of the length of your piece? Practice is an important element when preparing for questions that require long responses, not just for competitions such as ICAS, but also for a number of Stage 6 subjects. You should practise writing responses to a number of practice questions/stimuli. Doing so will allow you to become increasingly used to writing long responses in addition to expanding your ideas and developing patterns that help you link certain ideas to relevant questions. You can also do this under timed conditions to mirror those of ICAS. The more you do this, the more likely you will be to finish your response within the time limit.
Generally speaking, a creative piece should be structured in a way that enables you to focus on the following elements:
- A section that begins your creative piece, where you can familiarise the reader with the main aspects of the creative, such as the main character(s) and the setting(s) where the actions take place.
- A section that introduces a problem or challenge that the main character(s) will have to face.
- A section that showcases the problem's initial impact on the main character(s).
- A section that showcases the full impact of the problem on the main character(s).
- A section that showcases the way in which the main character(s) overcomes the challenge and concludes your creative piece.
On the other hand, a persuasive or discursive piece would adopt a more linear structure, with a clear introduction of the topic of your piece, followed by body paragraphs to explore your main ideas (you can start a new paragraph when you start discussing a new point), and a final paragraph to briefly summarise your main points and conclude your piece.
I hope this helps!