For creative writing belonging
1) Keep away from cliche stories, don't be the 10000th HSC kid with a school belonging story.
2) Seeing as you don't have the stimulus till exam, have a piece that could explore both belonging or not belonging, or have a sketch story for different types of belonging, like one for place, one for people etc.
3) Structure is the spice of life. Vary your sentences and the way you present your ideas through metaphors etc.. No matter what the story it makes it better.
4) Good grammar, tense and all that jazz.
5) Craft your story. Sometimes less is more, you don't want to tell everything, your story should speak to the marker in between the lines.
Any more specific Qs?