While the Fool comes first in the deck he is noted by a 0 instead of I due to his lack of life experience. The card we see as I is The Magician, the master of all.
Looking at the card itself you'll notice where the number 1 is marked there is a table laden with the symbols of the other four suits, also representative of the elements. The Chalice (Water), The Sword (Air), The Wand (Fire), and The Pentacle or Coin (Earth). This represents his control over the universe. The table can be seen as a work table which can represent his creativity, talent, and skill.
Around The Magician's waist marked by the number 2 we see a snake eating its tail also called the Ouroboros. The Ouroboros symbolizes immortality, and The Magician's power over the cycle of life and death itself.
Above his head marked by the number 3 we see the universal symbol for infinity. Like the Ouroboros this symbolizes his willpower to control the very fabric of time. The Magician will stop at nothing to be the master of all.
The number 4 points to the position of The Magician's arms. He has formed himself into a lightning rod which represents many aspects of his personality and purpose. He is balanced and conscious of the entirety of life. As above so below. It also symbolizes the concentration he utilizes in order to achieve his level of mastery.
Some key words you may consider when doing your own readings may be: Mastery, Control, Creativity, Talent, Skill, Immortality, Power, Willpower, Balance, Concentration and Conscious awareness.
If viewing the card as inversed perhaps this is a person who craves power without retrospective, or perhaps someone who uses their talents for negative ends. It can also represent someone who is the exact opposite of The Magician, someone who is weak willed or insecure.