Wanted to give a Step by step of one of my older pieces. Will try and post more of these in the future.
step one, block in the big shapes in 3d. I've laid out the scene in clusters by depth. I have foreground, mid ground planes and my background planes
begin a fast lighting pass. I knew I wanted the scene to have the eerie natural lighting from above but I also wanted some point lights to help fill out the lighting scenario
now I begin to add the haze and atmosphere. Also decided to add in a few more elements into the piece like the large structure over head.
More large lighting and value adjustments. I still haven't begun finer details or textures yet. Only until I feel comfortable with the general lighting and large shapes will I begin to tackle those.
Now that I have my large shapes, values and depth worked out, I start the details and textures pass. The character was added in at the very end of the process.