As a sophomore in high school, I am very used to the term DIY meaning Do It Yourself. Many people go out and buy items to create these DIY projects, when you can reuse and re-purpose many things. One of the big ones I see is the mason jar DIYs. Or any jar really. People take jars and use them to store hair ties and make up brushes even playdoh if you have kids. It takes thousands of years for glass to break down, and reusing glass bottles or containers really help the environment. Instead of throwing them away, and having factories use tons of energy, which pollutes, to make new glass, you just reuse it.
You can have friends over and make over many of your reusable items. Its fun and a great thing to do on a rainy day. There are many things you can reuse and make them your own. You can design your own bag and use it as a reusable shopping bag, or use empty cans to store colored pencils and markers. There is endless possibilities when reusing things. Its easy to look up ideas and add your own personal touch to make it even more fun.
When reusing you are keeping perfectly  usable things from going to a landfill. When trash is sent to a landfill it is covered so it breaks down faster. which produces methane, a powerful green house gas which is even more potent then carbon dioxide. Which is one of the biggest factors to increasing climate change.

In our modern age there is no limit to what can scavenged for (D.I.Y) products even in a broken pare of ear buds. In ear buds have wire and magnets both of which have limitless opportunities. even if you are not creative if you can fallow instructions you can reuse old or broken devices and items to make new things. Websites like instructables.com/ and magazines like make magazine are great resources for almost any (D.I.Y.) projects.   with the new developments in 3d printing technology you soon not throw plastic out but instead separate it by type and it will be melded down into material to be used to make new things.