Subject Prefect letter, help please?

Right so, to begin with, please don't confuse this with a senior prefect position. This is a subject prefect application, and I will be applying for graphics and science. Basically you need to discuss your qualities and why you would make a good prefect for that subject within the letter. I find it hard to find my qualities, so please could someone suggest a template or some possible qualities I could mention please? I'm good at writing letters, I just need a starting point to be honest. Thank you, any help is appreciated.