Layer the two pieces of fleece so the correct sides are facing out, and trim so the pieces are the same size. Make straight cuts 4 inches deep with 1 inch between each cut to make a fringe along each side. Tie the fringe pieces to hold the fleece together.
Find a large, clean work space such as a large table or a clean floor. Place the bottom fleece on the surface with the side you want showing facing down. Smooth the fleece. Place the second piece of fleece on top with the side you want showing facing up. Smooth the two pieces to remove any bubbles.
Trim along all four edges to get straight, even sides. Four inches is the average depth for cutting the fringe, but you can go slightly smaller or larger. Cut out a square from each corner with sides the same length as your fringe to create a cutting guide. Use a yard stick to mark the depth and space the fringe.
After cutting the fringe, you have equal numbers of strips on the top and bottom. Tie together the pieces that line up: one from the top and one from the bottom. Use an overhand knot. Work around the blanket until you have tied together all of the fringe pieces.