YOUR OTHER CARD
While the Birth Card is the card for your birthday, the next most powerful influence in your hand is called the Planetary Ruling Card aka YOUR OTHER CARD. It is the card in your hand that sits in the position of the ruling planet for your astrological sign. For instance: Mars rules Aries, so the Mars card in the hand is the OTHER CARD for Aries people. Your OTHER CARD might be just as relevant (sometimes even more so).
The reason someone with your same Birth Card might seem very different from you is because of this influence.
To find your OTHER CARD, choose your birth month.