How-to books and articles are everywhere, and anything and everything that you know how to do can be a subject for your how-to.
When you're writing a how-to essay, it's different from writing a how-to article. In a how-to article, you're describing a process so that someone else can learn how to do it too.
When you're writing an essay, you're describing a process to share an insight about life. For example, in a how-to article about backing up your computer, you're teaching the reader how to backup his computer. First you do this, and this… In a how-to essay, you're describing the backing up process to make a point.
Your how-to essay is similar to a narrative essay: at the end of writing your how-to essay, you need to discover the insight, the point you're making. This insight may not appear until you've written the essay.
Today, write a how-to essay. The essay can be about anything you know how to do. How to bake a pie, or how to create a backup program on your computer. :-)