Agree with others about NOT expressing it.
This has been a gradual process for me. As a sober Buddhist environmentalist, there are lots of things that seem normal to me that are weird to other folks (and vice versa). When I was younger (teens / 20s) I was pretty outspoken re: environmental things. Needless to say, that didn't make a lick of difference. I've found that as I've focused on my own actions, my impulse to tell other people what they should be doing has greatly diminished.
At the same time, I'm open with folks around me. For example, people I work with know that I bike to work, don't drink, meditate, etc., and I've had folks talk to me about all of those things at different times. I've also made myself available for advice w/ retirement planning. While I have had a couple people ask, I actually feel like this is more taboo (for other folks) than any of the other areas. It's kind of weird.
Similarly, w/ family / friends, I never tell them how they should live, but the difference between our lifestyles is pretty clear (when swapping vacation stories, for example). And we are very direct in terms of what we would / would not like in terms of gifts (especially now that we have a kid). That said, people sometimes follow our preferences and sometimes they don't. Fortunately, there's always Craigslist!
In general, I'm a big believer in the fact that you can't tell other people anything. You can't change them. If you happen to meet someone who is at a teachable moment in their life, and they sincerely want to change, and you have experience in this area, and they ask you for advice, there may be like a 10% chance that you can help them change. Even in these cases, though, habits are strong.