Hook your audience in the introduction by writing a captivating or intriguing sentence that gives a feel for what is to come in your essay. This can intrigue the reader to continue reading.
Tell an anecdote or brief story in your introduction that corresponds to your essay's topic to connect to the body of your essay. If you use a narrative story it will encourage your audience to read the rest of your essay. It is imperative you connect your thesis statement with the story or anecdote.
In your introduction, define any key terms that you use in your essay that the reader should know. This ties your introduction and essay body together.
Present your essay in the form of an upside-down pyramid: Start out in your introduction describing the overall big picture of your essay, and gradually narrow it down to you main topic's focus. For example, ask a question in your introduction relevant to your subject that you answer in the body of your essay. You can pursue this answer throughout the body and eventually answer it. Make sure the question relates to your thesis. A question also serves to introduce your topic.
Connect back to the introduction in an essay by linking the final paragraph -- the conclusion. Return to your introduction to reexamine your method of drawing in the reader's attention. Look for a connection in your introduction to link with your audience at the beginning of your conclusion. If your essay starts by mentioning a specific topic, person, phrase, word, quote, reaction, event, or occasion begin your conclusion mentioning the same. A memorable, well-known quote works especially well.