I am as sensitive to hearing "you should really be living THIS way!" lectures as the next person. Perhaps more so, because I live in California, where I have daily (daily!) "conversations" (lectures) with an astonishing number of people who feel the need to tell me how I am eating/drinking/exercising/sleeping/parenting wrong. Which is why I'm loathe to toe that line on this site; I am not in the business of telling anyone else how to live their life.
But I'm going to make an exception today, because when it comes to the environment it's way past time to sound those alarm bells. The reason I feel comfortable making the below recommendations is that I am a creature of enormous habit, and have historically been in the "What difference can little old me make?" camp - but from where I stand now, that attitude isn't just lazy, it's unacceptable. I'm also not someone who's very good at overhauling decades-old habits, but what I've discovered is that you don't have to do everything right: What matters is that you start doing something. Little things. Anything.
That's the way to start.