Help, I don't know how to talk or write

Embarassing as it is, it is also true. I don't know how to communicate correctly and in a beautiful way, neither verbally nor written.

I will start a master's degree next year and I want to use this summer to learn how to do it.

Do you have courses I could follow? Books I could read?

Thank you!

EDIT: Writing any assignment in school is a problem, essays are a nightmare. However, oral exams are also terrible as I cannot seem to formulate logic sentences and I end up making no sense most of the time, even if I have studied a lot.

I would like to learn how to express myself in a way others understand what I'm saying orally and in writing.