I usually start with a Charcoal Pour, what this involves is shaking powdered charcoal over a canvas or paper in a random way.
I try not to over think this part of things. Let it fall where it wants.
When I am happy with this start, I grab the tempera paint, red, blue for this work. I keep it to 3 colors at the most. I can always shake on more later if need be.
Canvas now with the blue
The canvas with the red. I may add another color later but for now I am happy with the canvas
I now spray the canvas with water and let the colors run.
I begin to lay down various textures, lace, metal strips, and from time to time leaves, ferns, grass, sand, whatever is needed to give me texture.
I cover the surface with plastic.
walk on it to press it down.
the canvas under plastic.
I now lay a large plywood board over this to weight it down and I let it dry. This may take several days. At this stage you cannot begin to tell what you have on the canvas.
it is a messy but fun process. I have no idea what it will look like or what I will see in the pour at this beginning stage. Once I decide what I see in this pour I begin to bring out the cityscape or a landscape using acrylic paint, inks, pastels and pencil.
Uptown and Downtown are examples of my work that are the result of such a process.