Reduce: Reducing the amount of waste produced is the first step in managing your waste. This is both a way to decrease the resources used to make the good (e.g. petroleum used to make plastic bags or straws), and decrease the impact during use and after having used the goods (emissions from plastic in landfills).
Reuse: If the waste cannot be reduced, waste should be reused, or repurposed. For instance food scrap could be given for composting, plastic bottles can be used to make eco-bricks, plastic bags can be used to make objects, and so on.
Recycle: If the waste cannot be reused, then it should be recycled (metal cans, plastic bottles, etc.).