Why do I ALWAYS do bad on tests?
Maybe you should appeal to the teacher her/himself for any study tips. There is a difference when taking a test if you feel a rapport with the teacher. But don't complain about the marks. Just hints for improvement. It could be that your conception of studying hard is less than others are doing. But make friends with the teacher. Again the idea that she is in your corner--which any teacher properly approached-- is can make a difference.
It may seem like your not doing well but if people know your trying or doing the best you can than thats what matters.