Turkey work is a fun way to add texture or fringe to designs. Start above the fabric and bring your needle down at A, leaving a tail on the top side of your work. Come up at B and down at C, covering A. Come up near A, under the back stitch, and back down at D, leaving a loop. Secure this loop by coming up at E and down at B, covering D. Repeat, creating loops and securing them with back stitches. Leave the loops intact or trim them. Securing the loops with back stitch makes them lay flat. Split the stitches instead to get fringe that comes straight up from the fabric.
Here's a video:
When filling a shape with Turkey work I like to think of how I would fill a shape with back stitch, which you can see in this video. You can fill with rows, or outline the shape and spiral in towards the center.
Turkey work is a fun way to add LOTS of texture to your hand embroidery work. Keep the loops loopy or trim and shape them.
If your loops are long they may get stitched down by subsequent stitches so I like to leave my turkey work for the end of my project.
Here you can check out the fun ways I used Turkey work in the Polar Pals pattern: