The Hidden World
Rebbe Elimelech teaches that Leah stands for the hidden world, and that is why most of the tribes, and most blessing, came from her.
The Noam Elimelech teaches that Leah and Rachel are two worlds: the hidden world and the revealed world. That is why Leah had to come to Yaakov in concealment, so that he did not know it was Leah. And that is why most of the tribes came from her, six sons, corresponding to the six directions, and one daughter: every flow of blessing comes from the hidden world. Rachel was the wife whom Yaakov loved openly. Leah was the one whose place was hidden at first, yet the greater part of the tribes came from her. What is concealed is not lesser: in Rebbe Elimelech's words, the flow of blessing itself comes from the hidden world.
Source: Noam Elimelech, Bereishis, Vayeishev (on Bereishis 37:2 and 29:23–25)
Leah's blessing came from the hidden world. This week, do one good deed that no one will know about: pay for someone's coffee and leave, put a few coins in a pushka without saying a word, daven for a friend without telling them, or clean up after others before they notice. Resist the urge to mention it later. Let it be between you and Hashem. Hidden kindness has a strength of its own.