One way to reduce waste is to: Reuse.
It is as simple as that. You don't need to buy bottles of water when you can buy a bottle and refill it with water. When you combine that with a home sink side filter you save a lot of money each year.
But there are other opportunities. By replacing disposable items with reusable items we can drastically reduce waste production.
There is of course a benefit to the environment but there is a personal one as well, an economic one. When I first heard this idea I thought to myself that it had to come at a price, either upfront investment or through additional time requirements. However, what I learned was that this, as with most things in our modern society can be quite easy. Compare a disposable plastic cup with its reusable equivalent: a cup or glass. The cup will serve once, for a drink or two and then it will be discarded. The glass cup can be served every day, or even several times a day for a very long time, indefinitely, unless it happens to break beforehand. Once you've exhausted all your plastic cups, not only will your trash bin be full, but you'll also have to go back to a store and spend money buying new cups. The glass will, of course, have cost more at first, but it will always be there when you want to drink something.
As a side note: When you have guests in the context of a grill party or other event where having everyone take a glass is impractical you can have cheaper reusable plastic cups on hand.
Reusing is also about giving new life to certain objects, especially via the used market. Flea markets, garage sales or websites such as ebay or the right corner or Amazon allow you to find almost everything for any occasion. The good thing is that many of the items that you find are more, for less new! They would otherwise end up in the dump. Personally, the last books I bought are -almost- all used books.
Composter are another are that you can focus on if you want to reduce your household waste. That, however, is a topic for another day.