Is there an art to thinking clearly?

I've been reading Rolf Dobelli's book, The Art of Thinking Clearly and I have found that there are many cognitive errors that keep us from thinking clearly.

Consider the titles of his chapters:
Don't Accept Free Drinks:  Reciprocity
Leave Your Supermodel Friends at Home:  Contrast Effect
If You have Nothing to Say, Say Nothing:  Twaddle Tendency
Live Each Day as If It Were Your Last--but Only on Sundays:  Hyperbolic Discounting

As I read the book, I found that my thinking began to become more muddled.  Logic was crowded out by fallacy.  I have always prided myself in rational thinking but I can see how emotions can impact decisions.  I was getting worried until I read the Epilogue where the author admits that he does not live an error-free life.  He sums things up in this manner:  "Nature doesn't seem to mind if our decisions are perfect or not, as long as we can maneuver ourselves through life--and as long as we are ready to be rational when it comes to crunch." (p 305)

Well, that sounds good enough for me.  Methinks I overthinketh.