One way could be eating less beef. Beef comes from cows, and cows produce the gas methane when they fart, which speeds up the process of global warming and so the less people that eat beef, the less cows are bred and reproduced, so there is less methane gas going into the air. Another way is simply walking or riding your bike in place of driving your car. Cars produce a lot of CO2, which is also bad for the air. Another way would just be to install solar panels on your house so you’re not using fossil fuels when you heat your house and turn in the lights and whatnot