Our life is dependent on Nature. If Nature is destroyed our life will also. In modern age human is only eager to get more and more from nature but he forgot to return to the nature back. If we don't return back to nature, the nature will also not return us back anything. This is the simple rule of nature of "equal reaction against every action" .
Therefore, in order to save nature, take steps to nourish the nature, by :
1. Keeping it clean and pollution free
2. Saving forests, plants, trees, rivers, mountains etc.
3. Saving Wild Life.
4. Planting new trees in abundance
5. Educating children about nature

The essence is, "If we can take care of our health, why can't we take care of health of Nature." Think about it.