This stitch is worked from left to right, along two parallel lines. Try to keep these lines equal distance from the seam line for the neatest look. Come up at the starting point along one baseline. Insert your needle at the next baseline, a little to the right of the origin point. Take a small stitch straight down. Now, insert the needle at the lower baseline, to the right of this stitch, and make a small stitch up the same length as the previous stitch. And away you go!
This stitch has a lot of flexibility. Add beads, knots, lazy daisies, whatever tickles your fancy!