I've been thinking about marketing and poetry books, and was interested in monitoring my reaction recently browsing in a bookshop about what led me to pick one up and what didn't.
Vague names are useless
Titles like 'Poems' aren't helpful. This isn't really surprising - otherwise there would be a lot of novels called 'novel', 'story', or '50,000 words'. (examples: Dylan Thomas Six Poems, Philip Larkin XX Poems, T S Eliot Four Quartets)
Poem names may not help
Wendy Cope's collections 'If I don't know' and 'Serious concerns' are named after good poems which feature in them, but as something on the spine of the book they sound unappealing. (examples: Philip Larkin High Windows, The Whitsun Weddings)
Startling phrases are best
An unknown poet needs to demonstrate that they have some facility with words, so ideally you should choose a characteristic example. (examples: W H Auden Look, Stranger! Wendy Cope Making cocoa for Kingsley Amis, Philip Larkin The Less Deceived). if the collction really doesn't contain one phrase which arouses curiosity, maybe there's something wrong.
Incidentally, price and cover art didn't figure as relevant - the one I bought was the one whose words seemed worth exploring.