I need help developing a thesis for "Ode to the West Wind."

When developing a thesis statement about a poem, you may be asked to focus on the development of a theme, or you may be asked to analyze how the poet uses specific techniques to create a theme or meaning in the work. 
When writing about Percy Shelley's "Ode to the West Wind," it's first important to know what an ode is; an ode is a lyric poem (a lyric poem is usually in first person, expressing the speaker's emotions) that typically celebrates the subject of the poem, in this case "the West Wind." Starting with this premise, we can read through the poem and try to discover what the speaker admires or enjoys about the wind and test whether the tone of the speaker matches up with what we would expect in an ode.
The first section of the ode depicts the dark power of the west wind. It is described as an autumn wind that drives dead leaves "to their dark wintry bed" (6), "Each like a corpse within its grave" (8) for the fall and winter, until the spring wind breathes life into the world again. Shelley speaks to the west wind in apostrophe, a direct address to an entity that is either not human or not present to reply to the poet. The poet addresses the wind as "Wild Spirit" and as "Destroyer and preserver" (13–14). The poet seems to admire the power of the wind, even though its job is to sweep death across the landscape.
The second section of the ode continues along the same thematic lines. The wind is again described as associated with the dying leaves of autumn. The wind is addressed as "Thou dirge / of the dying year" (23–24). The speaker ends this section by entreating the wind to "hear" him (28). The first two parts invoke and describe the wind.
In Part III, the speaker varies his imagery and depicts the changing of summer to fall. Therefore, we see more description of the "blue Mediterranean" and "sea-blooms" (30, 36). When those dreamy summer environments sense the west wind approaching, though, they "grow gray with fear, / And tremble and despoil themselves" (38–39). The wind destroys, but its awesome power cannot be denied.
Section IV sees the speaker put himself into the position of the leaf that might be carried by the west wind. The speaker becomes subject to the power, and here his admiration for the wind becomes most clear: he aspires to be "tameless, swift, and proud" like the wind (53). This section represents the most significant shift in the poem because the poet involves himself and his wishes, intertwining them with the powers of the wind that he describes.
This sentiment continues in Part V, where the speaker asks,

Be thou, Spirit fierce, 
My spirit! Be thou me, impetuous one! (58–59)

He wants his "dead thoughts" (60) to be swept away, across the world, like the dead leaves of fall. He wants to be free of the old and to be reborn. He ends the poem by saying that "Spring [cannot] be far behind" when we hear the the west wind (67). Again, the speaker admires the power of the west wind, wants it to help him begin again, and looks forward to the rebirth of spring.