Meta-Ethics

While normal ethics addresses such questions as "What should I do?", evaluating specific practices and principles of action, meta-ethics addresses questions such as "What is good?" and "How can we tell what is good from what is bad?". At its core it addresses the relativity of ethics (or moral relativism) is the concept that something that is deemed good might not be good for everyone. i.e. the words good or bad are relative terms and their meaning is entirely dependent on its contextual framing. So in these times, for people who want to do good, what would be most effective?