Soup kitchen once a month, treat homeless people as human beings when I'm working (nurse), donations to various local services who serve those people in need, health care clinic volunteer when they are sponsored.
Most importantly -- whether I'm working or just going about my day, I don't mistreat these people or look down my nose at them. I don't assume they are homeless by choice or too lazy to get a job. I don't get angry with them if they have a phone, clothes or anything I might not think they deserve. I know something is not going right in their life and hope they pull through and get the services they need.