In Lowell's answer in his interview what doorkonb means?
Don’t you think a large part of it is getting the right details, symbolic or not, around which to wind the poem tight and tighter?
Some bit of scenery or something you’ve felt. Almost the whole problem of writing poetry is to bring it back to what you really feel, and that takes an awful lot of maneuvering. You may feel the doorknob more strongly than some big personal event, and the doorknob will open into something that you can use as your own. A lot of poetry seems to me very good in the tradition but just doesn’t move me very much because it doesn’t have personal vibrance to it. I probably exaggerate the value of it, but it’s precious to me. Some little image, some detail you’ve noticed—you’re writing about a little country shop, just describing it, and your poem ends up with an existentialist account of your experience. But it’s the shop that started it off. You didn’t know why it meant a lot to you. Often images and often the sense of the beginning and end of a poem are all you have—some journey to be gone through between those things; you know that, but you don’t know the details. And that’s marvelous; then you feel the poem will come out. It’s a terrible struggle, because what you really feel hasn’t got the form, it’s not what you can put down in a poem. And the poem you’re equipped to write concerns nothing that you care very much about or have much to say on. Then the great moment comes when there’s enough resolution of your technical equipment, your way of constructing things, and what you can make a poem out of, to hit something you really want to say. You may not know you have it to say.
Here is the link of interview: