Does it help to say it comes with experience? Part of it is learning and becoming familiar with language features, and part of it is learning common programming patterns and technique.

With Perl, you'll never unlock the full power of the language until you see lists and how to put them together. If you realize that you're just manipulating elements of a list, map jumps out at you. Since print takes a list, it's easy to do the right thing and to decouple the transformation (HTML-izing URIs) from the action of printing them.

You don't usually see this all in one step, but if you do a couple of little transformations, you can open the door for bigger gains. They start to add up.