Use the TAKS study guides provided by the Texas Education Agency. The TEA provides detailed study guides for parents to use when helping children study for TAKS. Each grade and subject has a different guide that lists all the components of the test. You can use this guide as-is or create your own curriculum based on the information you find.
Download practice TAKS tests. Help your child get used to the test format with practice tests. These are actual past exams, not just sample questions.
Teach the concepts in a way that your child understands. One of the biggest advantages of homeschooling is that you can teach your child in the way that he learns best. For example, it may help you child to understand math concepts by taking a hands-on approach using blocks. An auditory learner may have an easier time with reading comprehension when she can read out loud--something she cannot do in the traditional classroom.
Set aside study time every day. While you don't need to follow the same schedule as the public schools, it's still smart to take some time out of every day to review the materials that are covered on TAKS. Create a study schedule so that you always know which areas to cover on that day.
Consider enrolling in virtual schools. If you're not sure that you can fully cover the material on the TAKS, it's time to bring in some help. By enrolling in online schools, your child can get the benefits of homeschooling with the same structure as the public schools.