In the spirit of Effective Altruism, this article is a good summary of which decisions in your life have an impact on the environment: Conscious consumerism is a lie.

Beyond making big lifestyle decisions such as choosing to live in a dense urban area with public transportation, cutting red meat out of your diet, and having fewer children (or none at all), there are diminishing returns to the energy you put into avoiding plastic or making sure your old AAs end up in the appropriate receptacle.