Burn less fossil fuels
Burning of fossil fuels (coal, oil, gas, etc) generates huge quantities of Co2. Fossil fuels are primarily used by transportation (cars, boats, airplanes) and by power plants. The less you drive or fly, the less fuel they need to burn, the less Co2 emissions.
Switch to renewable energy
Change your energy mix to a renewable energy source, such as solar panels, wind mills and waterdam turbines.
You can either install this at home (ok… a water dam may be tricky to install but solar panels can work) or check with your energy supplier on what is available. In many countries you can choose for renewable energy instead of using ‘grey’ energy.
Trees and plants absorb Co2 from the air. Replanting them or planting them in places where there were no plants or trees will help.
There are some drawbacks however as this can compete with other land uses such as using it for food production.
Direct Air Capture is basically a technology solution to capture Co2 from the air. This is still in early stage but it is a potential technology that could work to complement the above strategies. At the moment the cost per ton of Co2 is very high but this is expected to decline over next years.