Guardian: This year you’ve seen An Inconvenient Truth and rocked at Live Earth. In 2008, you want to know what to do to help save the planet but, with financial belt-tightening in the new year, you want to be able to do it without spending more. The problem is: where do you start? It’s the million-dollar question asked of environmental experts every day. Should you be saving energy, helping endangered species, cutting local pollution or supporting local shops? Should you aim for the biggest …