If you're preparing for the TExES Core Subjects EC–6 (391), the fastest way to improve your score is to study by domain, track weak areas, and practice with timed questions. What is the TExES EC–6 (391)? EC–6 (391) is the Texas educator certification exam for elementary teachers. It tests multiple subject areas across several domains. A simple 3-step study plan 1) Take a diagnostic to find your weakest domains. 2) Study one domain at a time with targeted practice. 3) Finish w