Apply to the Talent Managers Association. The Talent Managers Association asks its members to abide by a code of ethics, as well as provide them with various resources. Membership will help demonstrate your credibility as a talent scout.
Enroll in an entertainment management course through a college. Although there are no courses specific to being a talent scout, some colleges offer similar classes in their media studies or business department.
Obtain clients and make them successful. Although this is not a formal certification, it will go much farther in lending credibility to your services, especially if your clients are high profile or receive significant parts.
Create affiliations with organizations within the industry you are representing talent for and find a way to display that relationship on the Internet. One way to do this is to work as an intern with another talent agency. Although this cannot be done online, this work experience can be displayed on the website, lending to the appearance of a certified talent scout.