I can only add, that somebody coming from a less expressive languages might not understand hash expressions or hash and array slice expressions. Seems like every language has a PCRE library these days.
Oh, and to add to moritz idea, I tutored my co-workers on just that.
Plus, I included some instruction on Data::Dumper, Scalar::Util, List::Util and some very useful modules like that.
And why not for that matter, check out Damian's Perl Best Practices and snag a few of the more powerful suggestions.
