Really: few tasks are as fun and challenging as combining mediums. While the marriage between illustration and written word may seem glaringly perpetual, sustaining a complimentary dialogue between the two is nevertheless difficult.
I've managed to cobble together spur-of-the-moment methods to juxtaposing textual and illustrated narratives when having drafted comics in the past. However, I don't think I've found a method that I could confidently use again. However, I think that in this picture book collaboration with writer Shane Hosea we're managing to devise a useful drafting routine. So far, it's worked best for Shane to shoot me a written draft which I would interpret into thumbnails.
The idea is that Shane will then write his second draft while using the new visual elements to eliminate any superfluous text from the first draft - and when the second draft comes my way, I will similarly tighten up my compositions. What I find useful in this method is that the collaborative process is a dialogue rather than a dictation. Neither narrative elements are being bent around the other disproportionately. While smacking of fairness, this isn't solely a tool by which we're evening the work's authorship; rather, it optimizes the communication of the holistic narrative's ideas so that neither narrative element is being wasted.
With that said, we are only two steps through the dance. Plenty of time to step on a toe or two - or worse, prove myself wrong.
And I do hate proving myself wrong.