Start by recognizing and measuring the environmental areas (such as GHG / carbon emissions, energy use, waste and water consumption, and use of other natural resources) to get a baseline. This can be done internally or by working with a third party partner or specialized sustainability consulting firm on an environmental and/or carbon footprint assessment. I have seen many organizations set up internal "Green Teams" or eco-working groups to begin looking at measuring their company's carbon footprint. The most important part of this process is engaging both your employees as well as your suppliers. Carbon management is a team effort. It takes collaboration, transparent communication, and a willingness to see the greater benefits for everyone involved.