What you need:
A variety of leaves, pine needle bunches, holly branches, etc.
Glittery faux pinecones, leaves, flowers, etc.
Floral twine (basically wire wrapped in natural-colored twine)
Festive ribbon, twine, or yarn
Hot glue gun
Leaves and branches (unknowingly) courtesy of my dad's backyard - (thanks Dad!)
1) Make your wreath base by wrapping the floral twine into a circle three or four times. It's actually helpful if it isn't completely perfect, so you have more of a base to glue things on later. (Note: you can totally buy "premade" wreath bases, but they're much more expensive and not as customizable as just getting floral twine)
2) Squish the twine circles flat and hot glue gun the strands together at a few points around the circle so it stays more or less that way.
3) Start gluing leaves/branches/glitter onto branches, making sure to overlap them so the stems don't show.
excuse my fingers... pine needle sap...
You can also just weave branches into the wreath, like I did with these faux leaves into this (premade) wreath.
4) Add a big ribbon bow or just thread some ribbon through the middle and hang!
(anyone see the christmas lights DIY I posted about a couple days ago?)