An agile mind is the key
If you want to improve your eloquence, you must first cultivate an agile mind. Diligent thinking and brain exercise are the key. Only when the mind is flexible enough can it be proficient in verbal expression.
Recommend two books
I recommend reading two books, Eloquence and Personality Charm and Carnegie's Stomatology, which are very helpful to improve my eloquence. These two books can not only help us improve our eloquence, but also improve our personality charm.