When I first got the Sorby Texturing Tool I was told to run the lathe at a very slow speed. For the longest time all my results were crap. I would get it out once and awhile and try again and again to get acceptable results. After much experimentation here is what I've determined works for me:
Speed is my friend, I typically start ~500 rpm
Denser, fine grain wood (e.g. cherry, maple, beech) provide better, more distinct texture
I do my final sanding and seal the wood (I use shellac or brushing lacquer) prior to texturing.
I use a homemade tool rest made of round stock. I drilled a hole in it to insert a 1/4" bolt that stands up ~ 1" so I have a pivot point for the tool. I can control the tool so it doesn't run away if I cant it over. I usually approach the wood from below the center line, raising the tool into the wood. Once you make contact you must maintain contact or the texture pattern is botched. This is critical if you create a pattern with the tool canted over.
If I'm going to highlight the texturing I especially seal the wood prior to texturing. Next I lightly sand the nibs off but I'm careful not to cut into the seal surface. I apply gel stain with an acid brush with half the bristles cut off so it is stiff to get the stain in the texturing. Since the wood is sealed all the stain will wipe off leaving it only where you want it. After the stain is dry I will lightly seal it prior to doing my final finish.
I've included an example of a recent project. I hope this info is helpful but I'm also interested in hearing from others who've had success with the texturing tool.