There are many ways of working abstractly. Here is a website of an abstract expressionist artist. http://www.artistsnetwork.com/category/subject/abstract
I like to create abstracts in two different ways: either by abstracting what I see in nature or by creating a color scheme and a mindset or emotion.
First the abstraction of nature: In the piece above I painted a scene in Big Sur looking up the river. I used watercolor on a yupo support. The original painting is actually more representational and impressionistic. For the above I photographed the painting, cropped small areas that I liked and then rotated the cropped area. At this point I would like to do something similar in a very large scale. Notice that I used both warm and cool colors to create a contrast as well as value. What I liked about this particular section was the rhythm that was created across the surface.
Below is the original painting: I could also do this with a photograph.