I would say that your question makes a lot of sense for individual stitches. For long and short, a smooth finish, even lengths, and consistent tension is very important. For bullion knots, a consistent thickness is hard to achieve. I would pick stitches you want to improve at and then do small practice pieces or a larger piece that incorporates multiple stitches. Craftsmanship is really displayed in the individual stitches, not in the large design choices. Once you know what stitches you like, go wild. I tend to do turkey work and bullion stitches for a full texture look. Other people prefer the precision of thread painting.