This includes reading and analyzing the work of poets from classical to contemporary times, and developing insights into what makes their work worth reading. Knowing the craft of writing poetry means among that you could, if necessary, quickly produce a competent sonnet or that you can compose couplets nearly in your sleep. And, by the way, if you don't know what a pantoum is, then you need to bone up on your craft. Knowing the craft means you understand all about forms, and also understand how to break form intelligently. As anyone who's done bondage knows, wearing restraints is a liberating experience.
Poetry works the same way.
Form and meter are the ropes and chains of poetry. You must test them and resist them before you can hope to break them successfully. Meanwhile, some of us find the greatest freedom in remaining bound. With a bit of study, anyone can learn the craft. RedCrow has offered some good pointers, particularly to aspiring poets.