I read this in a book about guitars. It works for me. Start with every thing in tune. Then put left first finger on #1 fret and right thumb on #15 fret. Take right middle finger to fret #7 you should have .015 or 1/64 inch.between string and #7 fret. If too much tighten truss 1/4 turn to the clock wise. If distance is less than 1/64 loosen truss counter clockwise 1/4 turn and check again. Then lower untill you buzz and back off untill you don't buzz. As for E,A,D, they need a little more distance then the other strings because they move more with respect to the higher strings.