the thin poem has a few solid rules: one or two or three words at the most to a line and keep the subject simple don't muddy the reader's brain with poems about suicide or adolescence or the loss of beauty or innocence or some crazy time someone had at a drive-in movie a hundred years ago on a hot sticky night with a godzilla-like monster filling the screen while they were sprawled out on the backseat of an old chevy (and why is it always an old chevy?)
thin poems should not explore ******* or the rumblings of gastrointestinal distress or ******* or descriptions of the napes of necks or the sizes of ******* or the way certain people use their bodies in moments of intense passion
thin poems should center on lofty themes romantic ideals and maybe sometimes even ponder the existence of god
you could also write a pretty good thin poem about a spider skimming along a gossamer thread but i think that one's probably already been done to death