Add a README to the distribution. It should contain a quick description of your module and how to install it.
Add a MANIFEST to the distribution. Your buildtool should be able to autogenerate it (eg "make manifest" or "./Build manifest")
Add a META.yml to the distribution. Your buildtool should be able to autogenerate it.
Add a Makefile.PL (for ExtUtils::MakeMaker/Module::Install) or a Build.PL (for Module::Build and its friends), or use a distribution builder such as Dist::Zilla, Dist::Milla, Minilla.
Add a Changelog (best named 'Changes') to the distribution. It should list at least major changes implemented in newer versions.
Add a section called "LICENSE" to the documentation, or add a file named LICENSE to the distribution.
Add =head1 LICENSE and the text of the license to the main module in your code.
Run a proper command ("make manifest" or "./Build manifest", maybe with a force option), or use a distribution builder to generate the MANIFEST. Or update MANIFEST manually.
Error: Cannot find MANIFEST in dist.
List all used modules in META.yml requires
Add a META.json to the distribution. Your buildtool should be able to autogenerate it.
Add tests or move tests.pl to the t/ directory!
Move your *.pm files in a directory named 'lib'. The directory structure should look like 'lib/Your/Module.pm' for a module named 'Your::Module'. If you need to provide additional files, e.g. for testing, that should not be considered for Kwalitee, then you should look at the 'provides' map in META.yml to limit the files scanned; or use the 'no_index' map to exclude parts of the distribution.
Define the license if you are using in Build.PL. If you are using MakeMaker (Makefile.PL) you should upgrade to ExtUtils::MakeMaker version 6.31.
Add =head1 LICENSE and/or the proper text of the well-known license to the main module in your code.
Add 'use warnings' (or its equivalents) to all modules, or convince us that your favorite module is well-known enough and people can easily see the modules warn when something bad happens.
This is not a critical issue. Currently mainly informative for the CPANTS authors. It might be removed later.