I used a brush to cover this 24" x 24" canvas in a parchment background before beginning the foreground with a palette knife. Then I chose cadmium red to begin laying down colors with the knife, applying thick swaths of the acrylic paint.
Next, I added a few swaths of cadmium orange, and then used titanium white to set off these colors, being careful not to let the white blend too much with the red and orange. The last color I used was mars black, quickly swiping it onto the canvas to get a sense of sharpness and energy in the marks.
After that, I did a back-and-forth dance--adding more of this color here, that one there, blending the paint in some areas, being careful not to in others. Working with the palette knife is always tricky--you can get interesting effects by overlaying colors, and by using the knife to scrape away paint, leaving the under color.
My last step was to draw lines in black, outlining some shapes, adding texture, and defining the overall composition. By outlining a "negative space," for example, I could change it from background into foreground.
Stopping in time is also important--before you overdo an effect and wreck whatever the painting has going for it. I think I stopped in time on this one--when I look at it again tomorrow, I'll decide.