To explore metaphors more fully on your own, there are three directions you can go.
The first is simply to start noticing whenever you meet one. Jane Hirshfield slipped metaphors into many of the things she said in this lesson. You might listen to it again and make a list of some of the metaphors she used along the way, without pointing out that they were metaphors. Then go to any random web blog or newspaper or magazine article and just start reading until you’ve found a half dozen metaphors. Sometimes there will be many right away, other times there could be none at all. A factual, brief newspaper article, for example, is less likely to use metaphors or similes; but an article in which the writer is describing some event or issue that he or she wants you to experience for yourself will probably have some. Also, many ordinary expressions and sayings are metaphors and similes: “She was feeling blue.” “I was nervous as a long-tailed cat in a room full of fans.” “The news hit him like a ton of bricks.” Try making a list of some colorful or memorable expressions, and then look to see how many have metaphors in them. And pick up a few books of poems and find the metaphors in them. (Or look at poems online, on any of the websites listed below.) Not every poet uses metaphor, and not every poem, but many do. Hunting for them is one way you can tune your ear and mind to hear them.
A second direction to explore metaphors further is to practice inventing metaphors yourself. There are many ways to train yourself to think of metaphors. Here’s one: At any moment—you could set a cell phone alarm to go off three times a day to surprise yourself with the request—you can stop, look around, pick something completely arbitrary, then ask yourself to find a metaphor to describe it: “The big truck was weaving down the crowded avenue, a confident, nimble elephant in a hurry, seeming sure that the other animals would get out of its way.” “The half-dead flowers in the vase look like a cluster of disappointed kids, the ones who haven’t been picked for a team, standing there with their shoulders slumped, their faces closing up against showing what they feel.” “The refrigerator’s motor made a sound somewhere between a contented cat and an angry one.” Try many different kinds of metaphors to stretch your imagination. Notice when they just seem like playing around, and when you hit something that seems more interesting, more right, richer in feeling and information.
A third way to learn more about metaphor is to read about it directly. Many books discuss the special ways of using language that come under the larger headings of “figurative language” or “rhetoric.” This includes metaphor. One of the earliest such books is the Greek philosopher Aristotle’s Poetics. Much of what Aristotle describes there is as relevant today as it was in ancient Greece—languages change constantly, but the way the mind uses language was as fully formed in 600 B.C.E. as it is now.
A few specific resources:
Almost every modern textbook or handbook about poetry has a chapter on metaphor. The Princeton Encyclopedia of Poetry and Poetics is one good resource for an academic-level overview.
BBC Radio ran a terrific 45 minute program on metaphor (with a good “recommended books” list on the program’s web page). You can listen to the program in their online archive here: http://www.bbc.co.uk/programmes/b00w227c
A revelatory and now classic book about metaphor, exploring how language uses metaphor in subtle ways that don’t always seem apparent, is Metaphors We Live By, by George Lakoff and Mark Johnson. For instance, when we say something as simple as “That’s a big idea!” the word “big” is a metaphor: ideas don’t come in physical sizes. There are hidden metaphors like that in almost everything we say. When we say, “I see!” to mean “I understand,” we aren’t actually seeing with our eyes. When we say, “I understand,” we aren’t actually standing under the thing we’re thinking about.
Metaphors We Live By, by George Lakoff and Mark Johnson (IL: University of Chicago Press, 1980)
A more recently published book about metaphor and its function covers much the same ground, showing how metaphor affects us in every realm of speech and thought:
I Is Another: The Secret Life of Metaphor and How It Shapes The Way We See the World, by James Cleary (NY: HarperCollins, 2011)
To explore further how poems work in general, including many examples of how to unfold the metaphors in poetry without treating them like crossword puzzles to be correctly solved:
How To Read a Poem, by Burton Raffel (NY: Plume/Meridian, 1984)
Nine Gates: Entering the Mind of Poetry, by Jane Hirshfield (NY: HarperCollins, 1997)
Many poetry organizations and journals are online. One richly useful resource website: www.poetryfoundation.org
A search for the word “metaphor” within that site turns up an array of materials and discussions: http://www.poetryfoundation.org/search/?q=metaphor
A continually expanding selection of contemporary poems by poets worldwide, translated into English from many languages: http://www.poetryinternationalweb.net/pi/site/collection/index/en
For a similar resource collecting primarily US poets: http://www.poets.org