Stitch can be functional or decorative.  The subject of stitch, as it applies to embellishment,  is fairly simple for me.  There are many embroidery and decorative stitches, but really I have only a few basic stitches that I use, everything else is just variations on these few approaches.  The problem I find with a lot of the decorative  stitch out there is that it lies too loosely on the cloth and is less integrated into the surface.  Even in an art cloth I like the stitching to hold the cloth, to be more functional. So I stick to a few basics. My philosophy is that it is not always the stitch but how you use it and how far you take it that makes the difference. You might refer to the STITCH LESSON in Spirit Cloth 101 for an Overview.

Eventually each stitch will have its own page here, where I can elaborate on my personal approach. The menu below might grow with that in mind.

Sharon B has a great Free Stitch Dictionary, if you are interested in learning many stitches.