Can’t really see the target “vertical city,” I’m interested in seeing your visualization for it. Good job with the convincing concept sketches.
Even if you don’t have a set composition in mind for the final piece, you should start piecing together the elements of the story and image, as others have already said, that way you at least know ‘what’ it is you want to illustrate and ‘why’. Those should be the beginnings of the concept. The ‘how’ is the process that we are all working on till january. As it progresses, everything will morph. But if you couple your strength in illustrating ideas with a solid storyline and purpose, your concepts will become a lot stronger and more meaningful.
But sometimes, if you just have a small bit of inspiration, there’s nothing better than just sketching and seeing what evolves.
I’m anxious to see what you come up with… I’m sure I’ll have no problem following along with your imagery! good luck and take care