I would advise that you do some "practice" tests together, and talk about things like strategy, that a homeschooled child might not know, but a public school child is well aware of. Are these standardized tests? One thing which frustrates very bright children on multiple choice tests is that none of the answers are entirely correct, or they are too simplistic. Explain to your child that she should choose, not the "right" answer, but the answer that is the closest to being right. I would also recommend that you speak to your child's teacher to see if there are any other methods of testing that would work better for your child. Good luck!