I'm heavily involved with Austin Bicycle Meals [1]. When a homeless person already knows you are there to help, it creates an entirely different social dynamic than normal. You get opportunities to make conversation and connections, which humanizes how we view these issues.
That's a total reversal to how most people interact with the homeless: in an entirely avoidant manner either randomly on the street or through a car window. That's why so much of the general public is numb to their plight.
The change in mindset that happens is really powerful, can take only a couple of hours of volunteering to happen, and something I hope more people seek out.