Avoid abstract language—it won’t help the reader understand what you're trying to say!
Examples:
Abstract: It was a nice day.
Concrete: The sun was shining and a slight breeze blew across my face.
Abstract: I liked writing poems, not essays.
Concrete: I liked writing short, rhythmic poems and hated rambling on about my thoughts in those four-page essays.
Abstract: Mr. Smith was a great teacher.
Concrete: Mr. Smith really knew how to help us turn our thoughts into good stories and essays