First, it is very important to lay a good foundation, that is, to practice the basic strokes (horizontal and vertical) of Chinese characters first; This is what I learned with reference to Ding Yongkang's hard pen calligraphy course.
Secondly, because I don't like copying, I keep practicing on the basis of the first point, and then compare it with Mr. Ding's calligraphy, distinguish the advantages and disadvantages (by my own standards, hahaha), and foster strengths and avoid weaknesses. I often appreciate Mr. Ding's works in my spare time and benefit a lot.
As for the friend's saying that "writing well can make you write fast", I think it should be "writing well" first and then "writing fast". After writing well, practice makes perfect, and the speed will naturally be fast.