Walt Whitman's "Song of Myself" is an interesting work because it was completed over such a long period of time and revised based on Whitman's changes in life, experience, and thinking, though the substance and style remained essentially the same.
One of the primary symbols (there are many) in the poem is the extended metaphor of a journey. Whitman uses this idea of a journey aptly, since the poem took more than 30 years to metamorphose into its final form. The speaker (the "I" who is Whitman) shares his soul's journey (connection) to the earth, the ocean, with battlefields, and more. In section 46 he says
"I tramp a perpetual journey,"
and in section 51 he tells his readers that his journey will soon be ending and
"I stay only a minute longer."
In the final section, he leaves us (readers) so he can finish his journey.
Another constant symbol in the poem is the "grass." He refers to single blades of grass, leaves of grass (which is also the title of the poetry collection), and to grass as his grave, bequeathing himself to "the grass I love."
The form of the poem is interesting. Though it is commonly referred to as free verse, meaning there is no regular rhyme or meter, there is little doubt that Whitman does impose a kind of rhythm on this work. An out-loud reading will quickly demonstrate this.
Whitman uses repetition extensively throughout the poem, and he also uses anaphora, a kind of repetition which begins more than a few lines of the poem. Consider the "You shall" lines in the third section of the poem as well as the extensive use of sentences beginning with "And the" in the thirty-first section. Anaphora is scattered throughout the poem and is used to affect the mood of the work; reading these long lines without pause and in this kind of repetitive rhythm create a kind of chanting effect which adds to the meaning. The "And the" lines, for example, serve as a reminder that all of nature is equal and all are better than anything man has created or erected.
One of the primary motifs in this poem is Whitman's extensive use of lists to add emphasis to his point. In the anaphoric lines I just mentioned, for example, Whitman lists a blade of grass, the stars, a pismire (ant), a grain of sand, a wren's egg, a tree-toad, a blackberry hedge, a hinge, a cud-chewing cow, and a mouse. Look for these lists throughout the poem; they're everywhere.
The diction of the poem is also worth mentioning, as it is not written as most traditional poems of this time. Just as the poem depicts the everyday lives and experiences of ordinary people, the language he uses is a reflection of those same ordinary folks. Note his use of colloquialisms, slang, and dialect throughout this selection. He says, for example:
I loaf and invite my soul; I lean and loaf at my ease, observing a spear of summer grass.
This is not lofty language, but it conveys his connection to his fellow journeyers, which is all of us. In the sixteenth section, he elaborates on who he is in connection to his world, and he includes this line:
Of every hue and caste am I, of every rank and religion.
Of course such literary devices as alliteration (as in "rank" and "religion" in the line above), euphony, consonance, and assonance are easy to find throughout the poem and are all used as sound to enhance meaning.
It is also an interesting exercise to read the poem without the divisions. You will probably be better able to grasp the journey as a whole rather than reading it in what might be termed stages.