Cut your yarn into approximately 2 feet pieces. I cut 5 red, and then 10 pink, 10 orange, 10 yellow, 10 turquoise, 10 blue, and 10 purple.
Starting in the middle of your stick, create a simple larks head knot with the red yarn. A larks head knot is where you take your piece of yarn and fold it in half.
Wrap the loop end of the folded yarn around the stick and pull the two legs of the folded yarn through the loop.
Continue with each color down the stick till you get to the end. Once you have both sides complete, then cut one last piece of yarn in the outside color. My outside color was purple, so I cut a piece of yarn in purple approximately a foot long.
Tie each end of the purple piece of yarn in a double knot on each end of the wall hanging.
From here, you will need to cut the ends of the wall hanging. You can cut the bottom into a number of shapes. V shapes, off-centered v's, or the simple rounded bottom that I did for this to resemble a rainbow.
The easiest way to cut this the most precise is to mount your hook on your wall and hang your wall hang in place. Comb out all the pieces of yarn and then trim the bottom.