My parents sent me to a religious school as it's the best in the area but I don't believe in God what should I do?

This is a tricky one to answer.

You should talk to your parents to see what they think and how you should behave.

After all they actively chose to get you placed in that school and would have known that it was either against your religion or just a belief that you did not share yourself if as you say you are an atheist or a non-believer in God.

They should talk through with you what to do and how to act during religious lessons. Above all you must respect the views of others in that school and particularly since you are there through active choice.

If you like you could view the lessons as learning a story or as learning a history of some sort without committing yourself to belief.

If there are ceremonies that you are asked to pertake in, then you will need to think carefully about whether you should join in - again have a full and frank discussion with your parents who chose to place you in the school.