How to improve handwriting?

My handwriting is very messy and although my teachers can read it they sometimes complain. I can't read my own notes and mother never stops moaning at me, but I don't see what I can do. My attached and block letters are just as bad as each other and if I try to write slowly and neatly my hand and wrist start killing me. Not that it makes my writing better anyway. If anyone has any ideas please tell me. I've exams coming up and i don't want to lose marks over something as stupid as this. Thanks in advance.