Clarity of Thought

How does one know they have reached a pristine clarity of thought? How does one know their thoughts aren't logically flawed? How does one unbiasedly (understanding that it is hard to discount yourself) critique their thoughts and the thought process from which it emerges?

I have found myself many times living in a "fog" or "blur". Constantly bombarded by existential questions and even the ones that deal with daily life - like who are your friends? And the oh so simple question what makes a "friend"? These wonderings can drive you mad. Circling around and around in your thoughts with little difference between the conclusions you make in the end. It's frustrating. I seem to search for my answers in my life experiences, my observances of the people around me, and, yes, the Bible. So far I have a mass of information, but it's so much info that it's difficult piecing together common themes/messages/understandings/answers/conclusion. Which is why I am in a "blur". Too much info - like an overload.

The sensible solution is basically to dump (forget/ignore) all the info and start over, but that would leave me still with questions, yet, will a clear mind to start over. This solution is for now my only solution. How do you have clarity of thought?