Write lots of code that uses the most sketchy language features available. The chance is high that soon you'll get code that doesn't work. Now go through each line (source code or assembly) using a debugger of your choice and get it to work again.
Do this until there is nothing that will scare you anymore.
Also, do lots of maintenance programming. Finding bugs in code someone else wrote is generally much more difficult (and in my opinion valuable in learning sense), because you aren't familiar with it.
I'm curious what you think about how to teach the knack.