Eliminate unnecessary words.
For example:
John Major, who was once prime minister of Great Britain, is a man whom I respect.
This easily becomes:
I respect former British Prime Minister John Major.
Here you can cut the appositive, cancel two unneeded linking verbs, and replace the wordy prepositional phrase with a simple adjective.
Use the active voice in rewording a sentence. This means making the subject of the sentence responsible for the action of the sentence. The active voice reads more forcefully and is more concise.
For example:
The book was read by her with great delight.
This becomes:
She read the book with great delight.
Replace cliches and other tired phrases with words that more clearly reflect the point you are trying to make.
For example:
The heat was stifling.
Readers have most likely heard this too many times for it to mean anything. Instead, give specific, concrete details about the hot weather:
Though he had not moved, sweat soaked his shirt.
Change negative statements to positive ones.
For example:
He was not unhappy to be meeting her at the train station.
This becomes:
He was glad to meet her at the train station.
Distribute clauses evenly throughout your sentence, paying attention to rhythm and sentence length. This can mean either breaking a long sentence in two or combining two short sentences.
George Eliot, author of novels such as "The Mill on the Floss" and "Middlemarch," is the woman's favorite novelist of all time.
This becomes:
George Eliot is the author of novels such as "The Mill on the Floss" and "Middlemarch." She is the woman's favorite novelist of all time.
His wife was beautiful. She loved him.
This becomes:
His wife was beautiful, and she loved him.