There is no one-size-fits-all answer to this question, as the best way to become a certified proofreader may vary depending on your individual circumstances and qualifications. However, some tips on how to become a certified proofreader may include studying proofreading and editing certification programs offered by online or offline institutions, taking practice tests to improve your skills, and/or joining professional organizations such as the Editorial Freelancers Association or the American Copy Editors Society.