You take up the instrument of your art, cut a raw chunk of your heart for bait, cast as far into your imagination as possible and wait for something likely to strike.
Then you reel it in, slowly and with craft. With luck you have caught a poem. But quite often, just when you think you've got it, it simply slips away, leaving you alone, frustrated and bewildered, but still hoping it might be only another cast away.
Poetry is ephemeral; difficult to catch when sought. Hard to hold onto and easily lost when caught. All you can do is keep the poem in play and hope to land it another day.