An effective sentence is one that conveys the point you want to make clearly and persuasively to your reader. A sentence is clear if it does not have grammar and spelling errors. Additionally, clarity means the sentence uses the most precise words possible and doesn't have unnecessary wordiness. Paragraphs and whole essays are clear if they have topic sentences which tell the main idea and if the examples and reasons are explained logically.
Many of the examples in this article are not only about making your sentences clear; they are about making your sentences more persuasive. Writing effective persuasive sentences is a more subtle writing skill that involves tone, language choice, and sentence structure. In general, you are more persuasive when your sentences are professional, logical and varied.