In my opinion, an artist statement should be a concise two-three paragraph with the most relevant work an artist have done. The statement must contain names, dates or periods and places their work was accomplish and why the pieces should be important for the reader.
As well, the writter of the statement should include the relationship that has between their work and the environment, and should analyze the target readers in order to accomplish a usefull statement. Besides, the statement should be clear and must be written in a way the reader understands.
The personal statement should include the experience the author have had and what they are expecting to do in the future (their plans).
Finally, I think the artist must show their own style, so the reader or audience can get an idea of how the author thinks and expresses their work.
You can find a few examples at the links below:
- Architecture Personal Statement: http://www.studential.com/bio/getps.asp?ps=556
- About Frida Kahlo's Art: http://www.fridakahlofans.com/essay.html