I think one’s spiritual strengths are revealed through doing. For example, let’s create a character and call her Helen. Things are stressful at Helen’s office. During a tense negotiation, someone points out to her how patient she is being. Patience is one of Helen’s spiritual strengths.
Bob’s friend is telling him about the fights the friend is having at home. After a while, the friend looks at Bob and says, “When you listen, I get the impression that you are totally focused on me and nothing else.” Presence is one of Bob’s spiritual strengths.
We naturally have some spiritual strengths and we must cultivate others. I wanted to work on generosity, so everyday for a month I tried to tipped everyone who waited on me in someway–gas station attendants, the guy at the convenience market, etc. Not everyone accepted the tip, but they all appreciated the gesture.
I don’t know what your spiritual tradition is, but I am sure it has practices for cultivating qualities like kindness, gentleness, forgiveness, diligence, determination, compassion, etc.