The Thinker's Toolkit: 14 Powerful Techniques for Problem Solving

You might want to check out The Thinker's Toolkit: https://www.amazon.com/Thinkers-Toolkit-Powerful-Techniques-...

One of the books I still reread. Its not so much about "abstract thinking" but its very good at teaching you to find the real problem & make a decisions. https://www.amazon.com/Thinkers-Toolkit-Powerful-Techniques-...