When I straight line quilt I don't use chalk or pens to mark my lines, it's just to time consuming. Instead I use good quality painters tape to mark the lines. First, join your fabric to your desired interfacing, you can use something like 505 basting spray (I use that when quilting up to queen size quilts on my domestic machine), or for bags (especially cotton) when I want that extra stiffness/stability - I use a fusible web. I recommend something like Heat n Bond Light to join your fabric to the interfacing if it isn't fusible (I used by Annie's Soft and Stable in this case). But there's several great options out there. Use your walking foot for quilting, to make sure all layers feed evenly.
To start I just lay my ruler across what I'm to quilt at a pleasing angle and place my tape along it's edge. Then I sew the first line edge to edge with the tape with my walking foot. When I then have a stitched line to go after I just re-stick the tape along the seam line. This is why you want good quality painters tape, the good quality I can re-stick 10-15 times, while the bad one maybe 3-5.
If you can't find tape in the desired distance for your lines, stick it on your cutting mat and just cut it to the desired width. This one I cut down to 1/2".
And then you get this beautiful texture! So next time, don't hesitate to go for some straight line quilting, it's so much faster with painters tape! This is also a little sneak peek at my new pattern in the works.