* Not all artists can write well. If you're in that category, think seriously about hiring a professional writer or editor, preferably one with an art background, to help you convey what you want your statement to convey in language that ordinary everyday people can understand.
* Make "I" statements rather than "you" statements. Talk about what your art does for you, not what it's supposed to do for the viewers. This doesn't mean you start every sentence with "I," but rather that you respect people's autonomy and allow them to respond to your art however they wish.
* At all times, give readers the option to agree or disagree with you. Never pressure them or attempt to dictate outcomes.
* Avoid comparative or evaluative comments that have been made about your art by third parties such as gallery owners, critics, collectors, or curators. These belong in your bio, resume or curriculum vitae. In your statement, they're name-dropping; in your curriculum vitae, they're testimonials.
* Connect what your art expresses with the medium that you're expressing it in. For example, if your art is about world peace, and it consists of twigs protruding from pieces of clay, explain the connection. Arbitrarily stating that twig/clay protrusions represent world peace leaves people wondering. If of course, the object of your art or your statement is to leave people wondering, then that's OK. In art everything is OK, but in order to succeed as an artist, someone beside yourself generally has to get the point of what you're doing.
* Be specific, not vague. For example, if your art is "inspired by assessments of the fundamentals of the natural world," tell which fundamentals you're assessing and how they inspire you.