Experience is good, but I find some people have a "knack"... they intuitively understand when something is good and when not. How do you instill that? Priming from good logical and mathematical education help. Nudges to think for yourself and thins of the reason things are done a certain way sort of help. What more?

Lots of practice and experience.

Calling it a "knack" kind of downplays the years (decades) of study, work, and effort people put into refining their craft. You could also say Michael Phelps has a "knack" for swimming, but he also did nothing but workout, train, practice and compete for years.

I keep trying to explain this to my non-programmer friends: No, I'm not some genius, I read lots of information, and worked hard to get to where I was, and from a programming perspective, I'm barely competant and know just enough to be dangerous. Yes, you could probably do it too, although the difficulty varies depending on how well you can handle the kind of abstractions and logic you'll be dealing with.

That's actually kind of what I was trying to say...

CS is no substitute for experience, but it helps.