You definitely write better than you think you do, that much I can say for sure.

As someone else pointed out in another thread of yours, there's times when you're very clear like this and others where the clarity seems to be a bit jarbled - possibly this changes based on how you're feeling? That would be my guess anyways. Even when slightly jarbled I wouldn't know you're not a native English speaker. Practice will definitely help, and in my experience practicing through text does help with voice speaking as well, but you should try to practice with your voice when you can as well.