I feel guilty posting Henri Nouwen again, but to help learn how to embrace strangers with kindness is to always listen to what they have to say:
"Small Steps of Love. How can we choose love when we have experienced so little of it? We choose love by taking small steps of love every time there is an opportunity. A smile, a handshake, a word of encouragement, a phone call, a card, an embrace, a kind greeting, a gesture of support, a moment of attention, a helping hand, a present, a financial contribution, a visit ... all these are little steps toward love.
Each step is like a candle burning in the night. It does not take the darkness away, but it guides us through the darkness. When we look back after many small steps of love, we will discover that we have made a long and beautiful journey."