I am psycho about fresh air. We lived in the south for so long and only breathed air conditioned air, I couldn't stand it. Now we have an attic fan that sucks outside air through the whole house and we live in an area with really clean air. I love it and feel like it keeps out house "healthier" no clue if it really does though
Washing hands is a big one - my kids are pretty OCD when it comes to this because I always have been, it's nice to see them picking up something positive from me.
Lots of healthy food choices. Somehow I ended up with a house full of super active skinny kids (with a slightly plump mom

) they eat tons and all the time so I try to make it healthy stuff although it's tough at times because I have to cram the calories into them per our pediatrician (sort of an ironic dilemma for ME)
Tons of outdoor time - not hard to enforce but we have lots of outside toys, bikes, skateboards, jumpropes, balls of all sorts, basketball hoop, soccer goal, street hockey - I'll stop but the list goes on and on and ON.
So far (knock on wood) we spend very little time at the doctor and my kids miss very little school - hope it continues.
Martha