The Law of Correspondence states that the external world you experience is nothing more but a reflection of the internal world you have created for yourself over a lifetime. This internal world of course corresponds with the external world due to your dominant patterns of thinking, believing and emoting. In other words, nothing can happen to or for you in the long-term unless it first corresponds to something inside of you. As such, in order to change your life you must first begin changing the inner aspects of your mind.
This law therefore highlights the fact that absolutely everything you have and/or experience within the physical world, i.e. your possessions, health, financial situation, friendships, relationships, etc, were first created on the inside and later manifested on the outside. As such, all the problems you experience in life are of your own making. You therefore are the architect of everything that happens to you.
Given this, if you desire to change your life, friendships or relationships then you must first begin by changing yourself from within. Only in this way will your external world change as a result.