Know your subject. Some writers wait until they are nearly done with the essay before working on the introduction and hook. This saves time. Don't spend half an hour crafting a hook only to discover that your focus has changed and the intro no longer works as the essay unfolds. Once you are sure of your essay topic, think about some of the most interesting information about this subject in order to create a good hook.
Transform this bit of interesting info into an image by describing the subject in a unique way as a means to introduce it to the reader. This can be done by telling a story or setting a scene. Similarly, try relaying a dramatic incident. This is one option.
Relate amazing statistics or comparisons and/or contrasts in a way that affects the reader without sounding dry or boring; something to which the reader can relate. For example, if writing an article about how technology advances in the U.S., a good hook might be, "The technology found in today's simplest cell phone is more high-tech than the first space shuttle sent to the moon."
Introduce a person. Sometimes introducing a person or group of people will hook a reader, similar to the way an intriguing character can hook a person beginning a mystery or romance novel. The hook might be something this person said -- a quote -- or an action he performed. You may find a compelling hook in describing how the person looks -- it all depends on the subject of your essay.
Find your own writing interesting. If it bores you, more than likely your reader will find it boring too. If you don't find what you write interesting you might need to dig deeper or find another subject that intrigues you. If you are writing about yourself and don't find what you're saying interesting, maybe you aren't writing honestly enough. Think about something you would not want to share about yourself and write about it. The result might surprise you.