As you walk down the street, or through the mall, or where ever, focus on the people you see, one at a time, and say the Oramus prayer for them.
While at the mall, spend some time sitting in the Food Court, or on a bench, or anywhere that people stream by. Focus on them, one at a time, and say the Oramus prayer for them.
If you have more time, sit and silently pray the Rosary for the people passing by.