The Art of Complex Problem Solving

Recently I was interviewing few candidates from php background. Of course, I will not be talking about the interview. I found in one of the candidate's resume saying "Capable to solve complex problems".This just one liner triggered my thoughts from that day and I was curious to know as to how to enhance the problem solving capabilites and how to approach the complex problems.
I was discussing about this with quite a few people around me and I found a link that deals with exactly te same, "The Art of Complex Problem Solving".
This article deals with the following:

• Kinds of Problems
• Seeing the System
• Filling the vaccum
• Visual Modeling
• The Problem-solving System
• Process

Note:
For the benefit of Software Developers, please find the following links to strengthen your Troubleshooting skills and Foundations.
From TechMasala

• Foundations
• Troubleshooting