3 R's - Reduce, Reuse, Recycle
In the United Kingdom we have a Waste Hierarchy, which shows us how we should be dealing with the waste we produce.
The 'Reduce', 'Reuse' and 'Recycle' elements are referred to as the '3 Rs'.
Reducing: Try to reduce the amount of waste you produce, as this is the best way! If you cannot avoid producing the waste...
Reusing: Think of ways you could reuse something, like shredding paper for your hamster rather than buying bedding or saving glass jars for storage. If you can not reuse something...
Recycling (and composting): This is next as it enables the materials you throw away to be used again by making them into new products.
If items cannot be reused or recycled it is sometimes possible to recover the enegy that they contain through a waste treatment process.
Finally, for the residual waste for which none of the other options are possible, disposal in landfill is the last resort.