Edward de Bono, who was a physician, author, inventor and most importantly - the originator of the term Lateral Thinking wrote several books on decision making process. The most famous is Six Thinking Hats. Another good book by him is   Creativity Workout: 62 Exercises to Unlock Your Most Creative Ideas. His books are simple, logical and easy to understand.

I would like also to suggest a couple more books from the library's collection on the same topic:

• Great Decision Making Skills by Corona Brezina  
• Everything You May Need to Know about Decision-Making by Julie Parker.