Not too long ago I read the advice of a major poet (but I did not write down this advice, so I cannot attribute this) that each line of a poem should contain at a minimum three surprises. Three surprises--this seemed excessive and unattainable and so I did not write down the advice and expected to forget it.
But I haven't. And I'm glad I haven't, as this idea has improved my recent poems more than anything has in a long time. And I don't know who to thank for it; if you know, please tell me (I tend to think its one of the Charleses (Wright, Olson, Simic....not Bukowski or Baudelaire), but then again, maybe not).
I'm not sure what the mysteriously unknown major poet counts as surprises, but I have counted: especially effective line breaks, unexpected word choices, fresh images, imaginative use of punctuation, alliteration or assonance or other repetitions of sounds, internal rhyme, manipulations of the usual grammar, non-intuitive pairings of words, the occasional insight, unusual subject matter, anything that makes me think or read twice.
I also only aim for two surprises per line, as I am just a beginner at this. But lines that have no surprises in them suddenly jump out at me and demand their fair share. And it may be the highlighting of the weak line, the disallow of a single weak line, that is the biggest benefit to me of this technique: the idea that it's not enough for a line to be carrying the reader toward the next, better line.
When I read a poem, it is the sense of wonder and surprise that pleases me most, so it seems only obvious that that is what I should be writing towards. But it wasn't obvious to me. Until now. Surprise yourself, and the reader will likely also be surprised.
(Also, I like checklists; give me something to measure or count and I am all in. This technique really works for me!)