i think that perlintro is a great start.
by reading this you learn perl basics and you get directed to the more detailed perldoc pages of the section. and it can't be so difficult to miss perlintro, since it is listed as the second item in `man perl`.
if you have digged through all this, usually it gets easier and easier to find the right perldoc page for your question. if in doubt, use your operating system functions. i wrote my own perldoc-grep, which is basically:

exec("find",
  "/usr/lib/perl5/5.8.3", "-name", "*.pod",
  "-exec", "grep", "-H", "$ARGV[0]", "{}", ";");
[download]

so i can say pdgrep '<<[A-Z]', which will find me the docs to here-documents.