Commis chef cover letter, please help!?

I have just finished my GCSE's and i work at mcdonalds at the moment and i want a career as a chef and i am applying for a job as a commi chef at a hotel. i need help with a cover letter as i'm not very good with putting things into words. I want to some how say that i currently work at mcdonalds but i want to work for someone who is better (obviously not put it like that) who uses fresh food etc and isn't a fat food chain. I am hard working and enthusiastic and i want a career in food and i reeeally want this job. help!! xxx