Have you come across BDD at all? There's an associated change in vocabulary which I find really helps newcomers to TDD pick it up. Here's the vocab change:
http://lizkeogh.com/2009/11/06/translating-tdd-to-bdd/
I've found that using this language helps people focus on why it's useful to write the tests (or examples) first. I translated another example in the comments.
Even then, sometimes it's helpful to learn how tests are structured. If people have trouble learning how to write them first, writing them afterwards is a good learning step. You're right about the design benefits. It can take a while to grok.
In the past I've found that the best way to get TDD is to have a safe environment to practice in. Having my own toy app or running / attending workshops based on a toy app have both helped me a lot.
