Believed the balance is found within Earth, Air, Water, and Fire; I, like many others find there to be 5 essential elements- The Universe/Spirit (the non physical world).
I’ll explain my thoughts…
Fire, Earth, Air, Water all serve as powerful guides on how to live synergistically with nature.  
Let us go through our basic feelings. 
When you breath (Air)- you relax. Hence the idea of taking deep breaths.
When you see Fire- you become energized. Said to raise your vibration. The reference: “the heat and fire between us”
When describing flow, or “going with the flow,” we are referencing being like water.
When a guide tells you to “find your grounding,” its referred to finding your place, your balance, your oneness with earth. One of the most effective ways, is to find a place where you lay down or sink your bare feet to the ground to channel your energy flow and reconnect with your self roots. 
That instinct you feel, your “gut” wisdom- described as the non physical world, the Universe.
There is no one element more valuable than another.  It would be ridiculous to think so. The key is, finding the right measurements for yourself, to have the balance best catered to you. 
Each element has its properties that are needed and play specific rolls.
Where air represents intellectual intentions; there is earth that represents grounding and finding your valued substance. Where fire is a great representation of personal strength and movement; there is water that helps with not just emotional release but inner understanding. 
Each element plays a roll philosophically and methodically. Separated, one would say,
 “Fire gives light and historically plays the part of protection.”  
 “Air creates a start to something creative and new.”
 “Water with its wisdom explains the emotions’ one feels. We all have the power to change it”.
 “Earth is where we stabilize, rebirth so to speak, where some things either end or begin.”
Every individual has a relationship with all four elements. We all essentially play with the feminine and masculine.  It’s the combinations we choose to embrace that display our personalities. Let’s reference our 5 senses. What is your memory more connected to? Which sense do you use the most? I find these correlations to be interconnected. 
Bring forward self awareness, bathe in positivity, balance all outside influences in our moment to moment lives. 
I believe it is with our elements’ arrangements and synergy that Spirit is present.  
Best way to pick which element(s) to get for yourself:
Please note that every ancient culture has their own methods of choosing.
  • You can go off of what your element is by your birth chart. Similar to that of a birthstone. 
  • You can go off of meditation and feeling what you need.  Have a clear understanding of what is going on with you now, and if you would like a shift. 
  • Use the chart based on what is historically believed to symbolize the elements and choose based on that. 
From my experience and research:
Decisions to make, Refocus, removing the feeling of being all over the place, great for Studying: Element of AIR 
Worried, too much of a Dreamer, need Stability, need Self Confidence: 
Element of EARTH
Want Change, feeling Dull, New Relationship, need Courage, Passion, Love: 
Element of FIRE
(If you are already a feisty person, I will recommend you clear all your energy with Air prior to wearing Fire element, this energy in gemstones are commonly found in Carnelian, Ruby, Garnet gemstones).
Feeling close to achieving your goal but not there yet, helping make Dreams reality, setting Focus, keeping eye on the Prize, make your Intuition stronger: 
Element of WATER