Requirements:
authenticity - the profile must represent a real person, a registered company or organization;
uniqueness - this should be the only account of a person or company (exceptions are accounts in different languages);
fullness - bio, profile photo, at least one publication, no links to other social networks;
publicity - so that Instagram can check that an audience has really formed around you. you must be mentioned in the media and social networks.
Keep in mind that these requirements must be met at all times while you are promoting your account. After all, profiles with a blue checkmark are under scrutiny from both users and Instagram, because they are role models.