There are several forms that a poem can take. It is important to consider structure even though you may not feel that it is significant enough to write about.
Stanzas - couplets, tercets, quatrains, quintains, sestets (sixtains), septets. Consider why certain ideas are contained in separate stanzas
Free verse - no rhyming scheme
Shakespearean sonnet - 14 lines, iambic pentameter, three quatrains abab cdcd efefgg and a rhyming couplet