[q-base]

A lot comes with experience.

But I actually think that there is an "unconventional" way to foster the thinking behind it. Read/learn about philosophy. A lot of philosophy is basically breaking down/questioning assumptions. Some forms of philosophy are semantics-circle-jerking. But the thinking behind is very useful in a engineering setting. You get into the habit of detaching yourself and taking a step back from "conventional" understanding.

Also read "Surely you're joking Mr. Feynman" or see the video "The pleasures of finding things out" with Feynman. If you adopt that way of looking at the World around you, then you will quickly be a lot better at looking at problems from different perspectives than the one directly obvious.