Mi chino / italiano / inglés por tu español

I'm a native Chinese-Italian speaker and I have to pass a Spanish exams called DELE C1 (I haven't decided when to take it yet).
Soooo I offer my Chinese or Italian or my almost-native English in exchange for your perfect Spanish :D 

My current level is intermediate, I'd like to learn more vocabulary (léxico y tambien expresiones coloquiales) and practice grammar (verbos irregulares, subjuntivo, condicionales, imperativo ) and I need help especially with the writing part, because I have no idea how to write formal letters or articles/essays in Spanish haha.

I have experience as a language teacher and I'd like to find someone who's experienced in teaching Spanish as it would be easier to help each other :)