I've wondered what the "treasures in heaven" that Jesus spoke of in the Book of Matthew were. It seems clear that He was contrasting them to "earthly" treasures, that is, MONEY (and all that money brings).
Heavenly treasures are SPIRITUAL treasures. I struggle to hold "spiritual treasures" in high regard because my values are largely material (money based) ones.
Scripture defines the "fruit" of the spirit to be "love, joy, peace, patience, goodness, kindness, faithfulness, gentleness and self control." Whenever I can think, act or speak in such a way that demonstrates these emotions or elicits these emotions in others, I believe that I am storing up treasures in heaven. That is, God, being Spirit, sees/feels my heart and interprets my thoughts, actions and speech as worshipping Him in the spirit. That is my treasure in heaven.