Use your art skills to study for your math test. Drawing a sketch can often clear up the meaning of an equation or a complex word problem.
Familiarize yourself with the test. Take a practice test and go over the practice questions. If you are familiar with the question styles, you may be able to answer them faster.
Decode word problems. Practice writing out the underlying math equations, so that you can solve those rather than focusing on confusing words. You will need to read word questions carefully to find the actual equations.
Review the topics covered by the math section of the SAT on the College Board website (see Resources below). Most should already be familiar. If you do not feel comfortable with them, however, consider consulting your math teacher, a tutor or test-prep materials on the topic.
Practice eliminating choices on questions that you find difficult. Even if you can't find the actual answer through math, you may be able to eliminate enough wrong options to make an educated guess.