I'm not terribly into doing that myself mind you - mainly because there is so much to be done, it's a full time job for 10 people in our area alone. Instead, what I do is pester the people who do have a responsibility for keeping our built environment in a descent condition. Building owners, Councils, authorities of various sorts, government agencies, businesses, tenants and so on. What I have found is that in most cases, the people responsible for our built environment are so physically distant from it, they have no idea what condition it is in. They simply need a gentle prod from time to time to get out of their distant ivory towers and come out and scrub up the stuff in our suburb. So that's what I do - I act as a pair of eyes for what you might term "absentee landlords".
Not all of them appreciate that of course, but that's not my problem. That's somebody else's problem.