First of all, the moon can evoke many emotions. You have to choose one: affection, friendship, love and affection.
I don't think it is possible for you to write about love and affection, so I rule out these two.
How to write affection?
You can start with a small thing, such as what your family did together one night, and then express your parents' concern and gratitude through some details and dialogues.
It is also very important not to forget that you should associate this feeling with the moon, and don't simply write on the one hand and ignore it on the other. There are many ways to contact. You can describe the moonlight and night first, then write down what you think is good, and then contact your family. Insert a family-related poem and use some rhetorical devices, such as parallelism, questioning, personification and so on.
Friendship is also written from small things, which can be written about mutual help and love with classmates, or about things that finally get back together because of a small thing.
As for how to contact the moon, it will test your imagination. You can write about what happened one night, or you can introduce something about the moon, such as a pencil box, books and cartoons, or just some opinions about the moon that you are arguing about.
Secondly, if you choose one emotion to express, don't write anything else. The full text begins to write around these. You can use some techniques, such as writing in sequence, flashback and suspense. Of course, these are all ways to write a narrative.
I can't help you much if you don't write narratives, argumentations, even essays and poems. These things are not what you really feel, not from the heart, and you can't write well.
Finally, don't copy an article and hand it in. The process of writing a composition is not only a process of exercising one's writing style and improving one's self-cultivation, but also a process of feeling affection and friendship. This is a good opportunity, don't waste it.
Whether what I said is helpful or not, I wish you can write this article well and have your own experience.