Right now, I have my own homegrown testing harness/directory structure/support doc strucure/distribution tools for my libraries. However, reading the blog post Write your c
I usually start with Module::Starter. It comes with a pretty simple command-line tool that will create a new distribution from a template, including all the necessary files and a t/ directory, and so on. It will also produce either a Makefile.PL (using ExtUtils::MakeMaker) or a Build.PL (using Module::Build.)
It also places an empty .pm file there with templates in place for your POD and such.