Relax and don't worry about it. Follow your own gut feeling, be calm. No need to be rash or anything.
Have you ever worked with clay or something like it? Including touch into visualization that way can be really useful if it's already something you know how to do somewhat. Touch your tulpa's form as if you were molding it, feeling every little nook and cranny that their body should have if you were the one who has to mold it with your own hands. You could do the entire body very detailed or loose at first, or just take one part and really concentrate on feeling that one from every direction. The wrinkles, the pores, the hair... It all is there, if you wish to feel it. And well, massage is always something you could do, too.
Any visualization can help you to get better at visualization, of course. And narration is good too, so it's great that you have managed to make it a thing and stick with it.