If you have read nothing else, read these:

• Perl is my cast iron pan Well said.
• How do I post a question effectively? Thanks to the SiteDocClan for an excellent "How to I write a post" node.
• Use strict and warnings This is touched on in the above, but expands on it. Thanks to runrig for the excellent commentary.
• Writeup Formatting Tips Exceptionally handy.
• XY Problem. This is an excellent collection of quotes that may help you understand how better to ask questions. Sometimes the way you think something needs to be done is not ideal. If you're going to ask, state the whole problem. It may get you to think about your problem in a wildly different method than you are now. Thanks to jdporter for collecting these.

Modules I use on a regular basis:

• Log::Log4perl. Quit your homebrew logging. It probably isn't as good as Log4perl.
• YAML::AppConfig. Standardize your data serialization, even in your program configuration files.
• WWW::Mechanize. Browse the web, headless.
• Test::More. Start putting tests in your work. Get started with Test::Simple.
• Net::FTP::File. Fill the gaps in Net::FTP.
• XML::Twig. I haven't found a need for any other XML processor. Exceptionally powerful and usable.
• GetOpt::Long. Make passing switches and data into your s‎crip‎ts easy.