1. Reduce, reuse, recycle.
2. Upgrade your lightbulbs.
3. Check your water privilege.
4. Start your own compost.
5. Wash laundry in cold water.
6. Drive at the speed limit.
7. Turn off your computer at night.
8. Repurpose glass jars.
9. Use matches instead of lighters.
10. Buy locally.
Even if it's just fruit and veggies, any foodstuffs you buy that don't have to travel halfway across the country is better for everyone. It's probably the easiest thing of all.