Time to Fly is one of my latest commissioned paintings. 
It is a busy Time Square piece that started out as a sketch below. The client fell in love with it and requested a large canvas 60" x 72" which barely fits in my small studio at that time. 

Obviously the drawing below is pencil and doesn't show the color of Time Square. Along with my sketching a scene, I take photos of the area to use as reference material later. 

So, let's get to it. The first thing I do is get the sketch approved. The second is to agree on the size of the canvas, and the third is to pick a color scheme, season, time of day, and include any extra final touches the client wants. 

The client asked me to include faces of her family members into the scene, which I thought was a very cool idea. So, I will paint her family into crowds occupying Time Square.

The ever empty blank canvas, that is soon to be not so empty.

Laying down the underpainting. For most realistic paintings I make, I use an underpainting before I get started. It is a time proven tool used by the masters. Underpaintings are often monochromatic and help to define color values for later painting.

Giving it some texture as I go.

After the underpainting has time to dry, I will start blocking in color.

My first lines are painted without a ruler to get the composition right. I always prefer to rough in the outline of everything, and later go back and straighten things out with a ruler to make the perspective accurate.

Sometimes the rough line work gives my paintings a certain look and feel that I like.

Time Square is about the people just as much as the buildings, so here I am roughing in the people walking in various directions, along with the traffic of course.

I am adding some more color and definition to the subjects.

In this shot, it is a little more refinement, and bringing in colors throughout the piece.

Finally, I am adding some facial features and a little detail in the foreground. I've straightened out a few lines to make the perspective more accurate, but if you've ever been to Time Square, then you know everything seems like its on top of itself anyway. The painting at this point is about 70% complete in my mind. Which still seems far away from done.

Here are just a few of the raw detail shots before they get cleaned up.

My workspace for this painting looks a lot messier than it is. Now for the final shot. The finished painting with all of the detail of people, buildings, cars and advertising.