Been doing this for the last month and making every opportunity to say hi and chat to people who serve us.
The best one was talking to Janet who I have seen everyday for the last 5 years as she fills up the vending machine in the office. I was standing there getting some hot water and just said Hi. She said Hi back and see started chatting. It was really nice, we talked about her grandkids and my kids and it was only for 5 minuses or so but it felt great. It's now a regular occurrence.
I also now find myself just talking to people more asking "how are you today?" A simple question but really opens people up.