I like pedometers and things that measure your activity. I'm know we're all supposed to be sousveiliancing ourselves into a stupefied something or other but I like the way they easily let me pay attention to how much I move and walk about.
My fitbit - combined with beeminder - helps me notice how little or much walking I'm doing. I found out, for instance, that I walk a lot less at the weekends than I do in the week, and if you'd have asked me to introspect about that, I'd have said the opposite.
In 2013 I set myself a target of an average of 10,000 steps a day. I managed to do that. In 2014 I raised it to 12,000 and I made that. So this year I'm aiming for 13,000. That's going to require actual effort and lifestyle change, it won't just be a case of walking to work and wandering around a little at lunchtime, I'm going to have to make more concious effort. But it's a good trend - if I keep up this sort of progress I'll be walking hundreds of miles a day when I'm 80.