Organize the poems by theme. For example, you may group a set of poems together that each contain memories of childhood. Similarly, you may notice that one metaphor (such as trees or nightfall) unites a set of poems into a group.
Arrange the poems by form. You may choose to group together all of the sonnets, for example The same may work for a group of haiku or ballads.
Group the poems by style. If there are a number of poems that use a lyrical cadence to convey themes of love, for example, these may form a natural group. Similarly, short poems using rhyming couplets to evoke minute observations about nature might go well together.