The change of habit is, "Be more energy aware". As with all things, I'm trying to be moderate about this -- I don't want to turn into an Ed Begley-style energy fanatic, trying to save every possible erg. It's just a matter of paying a bit more attention, and start fixing the stupid and easy stuff. Unplug that TV that we haven't turned on in months, which is sitting there hungering for someone to press a button on the remote. When I change a lightbulb, ask seriously whether there is any reason *not* to replace it with a fluorescent one. Stuff like that.
The resolution itself is sort of like keeping kashrut: the little observance to keep the more important matters in mind. It's pretty simple: "When I'm not in a rush, and I'm on the highway, drive five miles per hour slower". Nothing dramatic or life-changing, and it's not going to save the world by itself. But it's a little change I can make without any significant cost to myself, which makes things better. It drops me from the high to the low side of average Massachusetts speeds. It kind of forces me to consider the process of where I'm going, instead of being solely focused on getting there as soon as possible. Overall, it probably has the positive side-effect of being good for my blood pressure. But mostly, it reminds me that the issue matters, and the little changes are worthwhile...