I have a piece of blue (painter's tape) for visual, and I use the edge of the foot and move my needle (Pfaff). If I am doing fairly large or long straight edge pieces, I clip a small plastic ruler to the plastic Sew Mate bed with a metal office clip, lined up with the edge of the foot and that gives me a good solid source to butt the fabric edge up to so I don't "sway" but it is also quickly removed when I don't need it any more. I make dolls and stuff too so I don't want something that is going to be cumbersome to switch back and forth. :-)
Marysewfun