Read through the blueprints published by the TEA for your particular grade level. The blueprints are available on the TEA website and they detail the material that is covered on the exam. The blueprints go over objectives for each subject tested in each grade level.
Review the Information Booklets published by the TEA for each grade and subject on its website. The Information Booklets give more information about the exam, samples of how objectives are tested, and more information about the objectives, also known as TEKS (Texas Essential Knowledge and Skills).
Work through the study guides on the TEA website. They are designed for students to work through on their own and for families to work on together. Choose the particular grade and subject you want to study from the chart on the TEA TAKS Study Guide page. These documents are in PDF format.
Go over past and sample exams available on the TEA TAKS site. The information and questions will be different than the ones that will be taken, but the questions are samples of the types that will be asked on the TAKS. Try to take the tests yourself within the time limits that would be given on the actual exam. Also review examples of good writing posted on the TEA TAKS site.