Quality 3x5 index cards have accurate 1/4 " spaced lines. Put needle down on the line and then butt a partial stack of "super sticky" post-it notes (the bound edge) up to the edge of the 3x5 card, when they loose their stickum just peel off a page and re-place. I used this fast and cheap method in my 4-H sewing class, sure helped those little girls!