Measure your impact.
The first thing is to get an idea of your own personal Footprint. Everything we do makes a demand on nature. The food we eat, the clothes we buy, the way we travel, everything.
Added together, the demands made by each and every on of us - humanity's Ecological Footprint - are far too much for our planet. 50 % too much, in fact. A good start for lightening you load on our planet is to first understand where your own impacts come from.