Ask the owner of the distribution (the one who released it first, or the one who is designated in x_authority) to give you a (co-)maintainer's permission.

List all modules used in the test suite in META.yml test_requires

Split the distribution, or fix the version numbers to make them consistent (use the highest version number to avoid version downgrade).

Add all modules contained in this distribution to the META.yml field 'provides'. Module::Build or Dist::Zilla::Plugin::MetaProvides do this automatically for you.

Add SECURITY(.pod|md). See Software::Security::Policy.

Add SECURITY(.pod|md) and add a contact address. See Software::Security::Policy.

Add CONTRIBUTING(.pod|md). See https://docs.github.com/en/communities/setting-up-your-project-for-healthy-contributions/setting-guidelines-for-repository-contributors.