I liked all of the responses. I thought I would add a few things. You can bring a horse to water but you can't make him drink :) A little overused, but guaging someones desire to learn is important. If they already know how to program and they want to learn perl, then they will learn it with or without you. If they're waffling in their desire, then more than likely they will never learn enough perl to use it on new projects.

Also, learning to read the online documentation and books for perl is important. The chapter on references use of the word "thingie" had me a little puzzled. Odd, considering I'm good with pointers in C, which is sortof kindof related.

Lastly, be willing to answer any question, regardless of how inane it is. Even the best minds are missing gears on some of the wheels ;)

PS. I don't consider myself good as a teacher, but out of about 10 tries at teaching it, I had 2 successes. The 2 successes were the ones that really just wanted to learn it. They taught themselves pretty well :) Come to think of it, I don't think anyone really taught me a whole lot about programming. I think they just kind of pointed me in the right direction.