To teach in the state of Texas, individuals are required to pass the Examination for the Certification of Educators in Texas. The TCA has compiled a study guid to help you prepare for the exam.
Each spring the Texas Classical Association and the Department of Classics at the University of Texas at Austin sponsor a free review for the Latin TExES exam. For details, including the date of the next review, click here.
There is a specific page called "How to become at teacher in Texas" which might be of use as well.
Good luck with your exams!