Artwork is a combination of form, materials and content. The forms and materials themselves may be the subject matter of the piece, as in various types of abstract expressionism, or artwork may be structured around a particular image or theme. One of the essential things viewers hope to find in an artist statement is an explanation of the thematic motivations that inspired the artist. Describing the themes and subject matter of a piece also allow the artist to explain "why" she chose this particular subject and treated it the way she did.
Artists are influenced by other artists and many other elements and influences as well. An artist statement should describe some of these influences in detail. Artists are influenced by things on an unconscious and conscious level but may not be fully aware of major influences on their work. However, taking the time to point out obvious artistic influences provides important information to the viewer. Political, social, religious and personal influences have always played a significant role in art and in artists' lives.
An artist should always include a critical assessment and evaluation of his work at the time the work is created. Explain how the pieces on display fit into your overall artistic trajectory. How does it relate to previous work? What do you think you have accomplished? How does it relate to your future artistic plans and projects. How do you think your work interacts and relates to the contemporary work of your peers and colleagues?
Describing the materials and technique used in your work helps the viewer to better understand and appreciate what they are seeing. The artistic community develops and grows through the free exchange of knowledge and information. Art evolves as new techniques or ideas are discovered and shared.