I use the same process for composing all of my songs. My goal is to create dramatic music to express and magnify the meaning of the poem. I compose the vocal line first, custom crafting the melody to emphasize what I consider important in each line, but also taking great care to set the words properly for the singer. This enables the singer to then communicate the words effectively to the audience. My motto, adopted from soprano Lauren Wagner, is "a happy singer is a good singer."
I always have some idea of the harmonies when composing the vocal line, but I do not flesh out the accompaniment until the vocal line is complete. I typically craft the accompaniment to color the emotions behind the words, and all musical aspects (rhythm, textures, etc.) are chosen to add additional layers of interpretation to the poem itself. Each song thus becomes my musical interpretation of the poem.