The 5 R's to Sustainability:

Reduce, Recycle, Reuse, Rot, Refuse
Reduce the quantity and the kind of products you buy. Consuming less reduces waste production.
Recycle paper, plastic, metal, and glass.
Reuse what you have. Repurpose, sale, donate, and buy used. This reduces waste production and saves money.
Rot nontoxic wastes. Compost food waste, plant trimmings, leaves, flowers, weeds, and paper products. The end product of composting is an excellent fertilizer. 
Refuse management. Be proactive by designating specific trashcans for plastics, papers, metals, glass, compost and landfill.