I am the worst at spelling and puncuation?

i have no ideahowto spell or when to use puncuation i am the worst at it like i will do a paper for school and its so bd people dont no what im trying to say.....im good at every cl my brades 90s or above but my english not so great....what can i do do fix this problem i will try to spell something right and it looks weird to me???? i need help lol