Start by tying some twine to each end of your birch branch for hanging.
Add some Christmas greens -either fresh or faux with some wire. I used some fresh white pine for mine.
Make some pom poms and tassels with some yarn, using a pom pom maker or a piece of cardboard. To make the pom pom with cardboard, wrap yarn around a rectangle of cardboard that's about 1 inch tall. Tie a longer piece of yarn around the middle of the wrapped strands on one side, and cut the wrapped yarn in the center on the opposite side that it's tied. Then use your scissors to trim the pom pom into a ball shape. To make a tassel, wrap yarn around a 2 ½ inch piece of cardboard. Tie the wrapped yarn at the top with a long piece of yarn. Cut the wrapped yarn at the bottom. Then tie another piece about 1 inch from the top, around all the yarn pieces. Trim the bottom so that it's even.
I used black and white, and a little red to make it Christmas-y. There are three pom poms on mine, along with 4 tassels. I also added a few wooden beads to the 2 of the tassels in natural wood, white, black and one gold for a little Christmas sparkle. You could make these in any colours to match the rest of your Christmas decor. If you didn't want to add pom poms and tassels you could try adding pinecones, berries, or bells with some hot glue, and tie on a traditional ribbon.
Attach the pom poms and tassels to your wreath with yarn or wire, about ⅓ of the way from the end of the birch branch.