It starts with energy. And where you live. Living with minus 20 degree winters in Montana or the Dakotas or 110 degree summers in Phoenix immediately places you in the minus column due to energy consumption. Here in western WA I use relatively little heat in the winter and next to no AC in the summer.
McMansions are popular with middle class Americans, yet in post WWII a majority of American families of 4 lived in 1200 sq foot homes. The difference between what we need to live comfortably and what we want has a huge impact on energy and commodity consumption. I have a daylight basement that has a thermostat set to 60 unless we have guests, and the heat never comes on all winter except in during an extended freezing spell, which we don't have much of.
Most of my life I have coveted an F-250 V-8 hellfire belchmobile that does nothing but waste gas when driving to and from work or day trips fishing, hiking, etc., which has always been the majority of my driving. Instead I walked the talk and drove a VW Beetle when it was a cult thing, a Datsun pickup because it did most pickup stuff, and several Subarus because they have done 90%+ of what I needed from a vehicle, all while sending less of my hard earned money to Saudi Arabia via Chevron and others. Then I saved even more potential gas money by re-acquainting myself with bicycling and got a lot of exercise while I was at it. But that ended up becoming a hobby, and I ended up with 5 bikes, so maybe conserved a little less than I could have.
My footprint could be smaller if I could consumer more locally produced and made stuff. That's becoming more difficult all the time because food production is centralized in CA's Central Valley and Mexico and trucked here, year around. I should source my beef as locally grassfed instead of Nebraska grain fed, but I don't discriminate and just buy steaks by the pack at Costco. Chicken is local, but the grain they're fed most likely isn't. At least the fish we eat is mostly local.
Plastic is the hardest thing to avoid. It's nearly impossible to buy things that aren't packaged in it. I recycle as much as I can, and our trash can typically gets 2 small plastic bags of garbage per week. So we're trying. I do wish all the glass beer and wine bottles could be re-used instead of recycled. Takes a lot of energy to turn perfectly good beer and wine bottles back into beer and wine bottles. How did we get here from back in the days when we had to pay a deposit on beer and soda pop bottles and they were cleaned and re-used?
Fortunately all that plastic that is a by product of distilling gasoline from crude oil doesn't all become throw away packaging. Some of it is made into carbon fiber for fly rods. And it could be said I've done my part to encourage that particular use.
Live close to where you work. Generally, you use more gas going to and from work than anything else. Plus, they don't pay you for windshield time to the office. I've lived in super rural areas, the suburbs and "in the city".
If you care about your footprint, it's tough to have a small one in a rural setting and work away from the home. The suburbs can be almost as tough.
A small house is helpful, insulate the attic, get better windows, get a more efficient heat source.