What makes a good poem? How the hell can I write one? And even if I did - what's the point!?

All valid questions, particularly on National Poetry Day.
Luckily, it need'd fall to us to answer - the great poets themselves like chin-wagging about their craft almost as much as they did scribbling down verses.
So whether you're looking for advice, analysis, or even a good laugh, we've compiled the poetical musing for you. Enjoy.