I will second the Beckmann recomendation. As Beckmann has said carpet carving is one step, but if you are straight lining on a very gentle slope, or typically a cat track in a relaxed state and the board is running straight, then you have attained nirvana. If you have to have muscle tension in order to run straight then you have to consider hard where the pressure is on your boot cuffs, ankles and feet, and what changes you might have to make to reach "neutrality"