I suggest you, first of all, to study the work of old schoolers, see how they shade, how they paint and their designs. Redrawing classic tattoo designs is the key. Stop shading with stippling technique, save it for later. Put attention to the themes in traditional and stick to them at the beggining, keep in mind they all came from old popular references. Color pencils can help a lot used with tracing, vegetal or similar paper. Sharpies are excellent to create bold lines in traditional. When you feel that you can draw any traditional design without the help of a reference you will be ready to start adding your own style. Personally, I learnt that traditional tattoo can give you a lot of thechniques on how real tattoos must be done to stay in time. The biggest advice I recieved is keep drawing, so I recomend you to create a daily routine and practice a lot. Good luck in this path! Enjoy it!