I have had people ask me how I can be so sure of finding insights, or helping other people find them. I wish I could tell you I had a brilliant answer ready to hand, thereby reinforcing my insight-guru mission. I was thinking about this today.
One way you find insight is to develop a lot of good questions, and be willing to open your mind to ask these questions. It helps to organize the environment to be conducive to asking questions (even silent ones), but the questions themselves are paramount.
I saw a great list of such questions today, aimed at helping people solve problems, which is known as the Phoenix List. It is purported to originate with CIA training, but who knows? [And who cares. It's a good list of questions.]
The list is published in Thinkertoys, an excellent book of creative thinking techniques by Michael Michalko [see resources below]. The list has also been reproduced online in a few places, such as here and here.
So I guess the answer is actually a question. Find good questions. Ask them. Listen. Ask more.
Thinkertoys, by Michael Michalko, 1991 + 2006, Ten Speed Press. There are so many methods in this book, it's a bit overwhelming. But it works very well as a desk reference, a place to find new ideas, as well as many of the classics, such as the SCAMPER method. I like that it uses business examples, and acknowledges the reality of the workplace (lots of people who are not comfortable with creative thinking methods).