Every year since 2006, a California-based organization called "Ethical Traveler" has released a list of the Ten Best Ethical Destinations for travelers to visit. These are developing countries who (to quote the organization) "are doing the most impressive job of promoting human rights, preserving their environments, and supporting social welfare – all while creating a lively, community-based tourism industry." By choosing to visit these countries on our travels, we can use our economic leverage as travelers to support best practices.
The complete list for 2014 (in alphabetical order) includes The Bahamas, Barbados, Cape Verde, Chile, Dominica, Latvia, Lithuania, Mauritius, Palau and Uruguay. Ethical Traveler does not rank the countries within the top 10.
ToursByLocals has guides living and working in eight of these countries (every one except Cape Verde and Palau). Some of them offer "eco" themed tours; all of them offer unique, personal insight into the local culture, so that you go home with a better understanding of the cultural, political and environmental issues at play in the place you're visiting.
If you're interested in learning more about how Ethical Traveler creates its list, or want to access more resources to help you choose where to leave your travel footprints, you can visit: EthicalTraveler.org.