I'm so glad to hear about the index cards having 1/4 inch lines - never thought about it. They'll make it even easier to draw lines on my machine.
I use a permanent marker right on my sewing machine - an extra fine Sharpie - to mark BOTH the center line straight out from the needle and 1/4 inch lines both right and left of the center line - right down to the front edge of the machine. Don't panic, it wears off, or you can wipe it off with 409 or a baby wipe, if that sort of thing bothers you. If it REALLY bothers you, put masking tape on the machine and draw the lines on that.
The center line helps you line up sewing corner to corner miters, and triangles. If you need to sew a SCANT 1/4 inch, just sew a scant bit away from the line.
I mark BOTH right and left, because when you sew strips and then more strips or when you're using the fusible grid system for a watercolor quilt, you'll eventually have to sew on the LEFT side, and moving your needle to the left 4 or 6 'clicks' isn't always exactly the same as moving it 4 or 6 'clicks' to the right. I was very frustrated until I actually measure this on my beloved Pfaff's open toe foot (albeit, an old one). Maybe the new one I just bought will be better - haven't measured it yet, but I will!
I hope this isn't confusing. You don't have to move the needle if you use the drawn lines on the machine.