The three practices that could make me a conscientious consumer are the following.
The first one is paying my utility bills on time. It is not only a matter of self-discipline but also a demonstration of my conscientious community membership.
The second practice I would mention is recycling packages. It is necessary to do it in order not to waste non-renewable resources.
Finally, the third practice is learning about goods before buying them. If their production brings harm to the environment, it is better not to purchase such products. Instead, a conscientious consumer will search for an adequate alternative that is, at least, less harmful. My strong conviction is that the human should try to preserve the environment by such simple acts. If everybody behaves this way, the ecological situation on the planet will get much better.