As you move through your every day life, look at the hats worn by older gentlemen - and occasionally the older woman. You'll be surprised at just how many of those hats tell you that the wearer spent some time serving this country.
When you see one of those hats, thank the wearer. I'll even tell you what to say: "Thank you for serving.", "Thank you for your service", "Coffee's on me today, thanks for your service.".
It doesn't take any time, it doesn't change your politics, it doesn't cost you any money (except maybe if you choose to pick up that coffee). You don't even have to engage in any further conversation. Just say it.
It makes the day of a person who never expected to be thanked for their service, and it's the right thing to do.
I have spoken. Go forth and have a nice day. Unless you are in Australia where I belive that it is Noon tomorrow. You have a nice tomorrow.