The Four Hebrew Worlds are (from the top of the tree):

Atziluth, the world of Origination or Emanation (abstract ideas)

Briah, the world of Creation (ideas linked to form concepts)

Yetzirah, the world of Formation (concepts integrated to form a plan or schematic)

Assiah, the world of Manifestation (executing the plan, doing, making)

These four expressions of the cycle simplify and clarify the greater cycle of the Tree itself.  Our thought processes work along the same lines.  We evolve new combinations of raw data (Atziluth) to form ideas (Briah) which we then refine and adjust to integrate into our lives (Yetzirah) before we actually put them into effect (Assiah)

In examining the Sephirah that make up the context of the Four Worlds, we can receive a clue as to how we may encourage those elements in our lives or to more effectively utilize those elements in practical application.