"Achieving unity in your compositions will only result from practicing, knowing and selecting the right visual elements and using the best principles of design to relate them."

I chose this quote in particular because when you first try to use this concept, it is pretty tricky to know exactly how to utilize each element. while using these elements you would have to know the difference between each of the elements such as: Balance, Movement, Emphasis, Contrast, etc.
As you practice with these one of the key things to remember is individual elements within as work of art should not be competing for attention and the main theme that is used should be understood very clearly.