Like his literary idol Walt Whitman, Allen Ginsberg is known for his super-long free verse lines. His poems many not be organized by traditional rhymes or meter, but they are held together by these long, meandering lines that seem endless and take all your breath away. Sometimes, the lines may seem almost like prose (non-poetry) in that they look a bit like little paragraphs.
Plus, Ginsberg was famous for his artistic iconoclasm and penchant for rebellious ideologies. So if you're reading a poem with lengthy lines and references to the evils of consumerism and the woes of boring old suburgatory, chances are you're reading Ginsberg. If it's set in California, then you're definitely reading Ginsberg.