Mighty
Never use mighty in the sense of very, or exceedingly. It is not only inappropriate but inelegant.
Of, From
“She had consumption and died from the disease.” Say, “died of the disease.”
On, Over, Upon
“Mary called upon her friend.” Say, “called on her friend.” “The Senator prevailed over his friends to support his bill.” Say, “prevailed upon his friends.” “The candidate prevailed over his enemies.”
Partake
This word means to take a part of, to share with another. It is often incorrectly used for ate, as “He partook sparingly of the food.”
Powerful sight
This is a Westernism to be avoided. It is used indiscriminately for a large number, a great quantity, a vast amount, etc.