A first principle is the fundamental building block of an idea, the most indivisible part that we know to be true and that we can use to build more complex thoughts.
Thinking from first principles is not a new idea. It's actually the single most consistent factor among great thinkers.
For example, Aristotle believed that you could not possess true knowledge without first understanding the first principles. He thought that everything could be divided into categories and sub-categories (the smallest of them being the equivalent for first principles).
An empiricist is a person that believes all true knowledge is based and obtained through experience.
The process of seeking knowledge through experience and making use of reason to give it structure it how we can find the first principles of a subject.
Once a first principle is understood, we can look and improve each component (from the simple to the more complex) of a subject or a product.
If every part is remarkable, then the total is remarkable.
Write down and organize information. Create hierarchies and mind maps.
Most ideas are nested outside or inside one another. You have to learn to map out how these ideas are linked.