The Camel book, hands down.

Most of the experience I have in Perl comes from writing my own utilities. Surely there's some task you do all the time that you'd like to automate.

Here's one of mine: 'anew', a program that does nothing but create new files from a set of templates. You say something like 'anew example.tex' and it creates a new LaTeX file with all the appropriate headers and setup. Right now I can cut out a new perl program, perl module, C program, LaTeX document, HTML document, and even a new GNU Lilypond file--already set up for use as a jazz lead sheet (chords, lyrics, melody).

Now you could do the same basic thing with a shell script. But I added enough bells and whistles onto mine so it performs other useful functions:

You can say anew example.pmo and it will create a new file called example.pm, with the skeleton of an object oriented perl module already in place. Same thing with example.pmf (creates a functional example.pm module).

The program 'anew' itself responds to --help and --version. Handy in case you don't have to use it for a few weeks. The documentation is embedded right into the program using pod.

Whenever I need anew to learn a new type of file to create, all I need to do is 1.) make a template and store it in ~/share/anew and 2.) add one more entry to a hash in ~/bin/anew

So my recommendation would be: find a need. As you work on the program, you will find yourself inventing new features, and learning how to implement them.