One of my very favorite kinds of quilting is organic straight-line, and it's as low-stress as it gets. Though it's even simpler than doing actual straight lines, I've had enough people ask about it, that I figured it might be helpful to finally share my technique.
First off, a well-basted quilt sandwich is a must. Personally, I spray-baste, and that's an ideal method for this style of quilting. I press the sandwich after basting, and also occasionally during the quilting process, just to keep things as smooth as possible. Registration lines are made with my ruler and hera marker, usually about 3" apart, or whatever works well with the design at hand. Sometimes I'll have a project where the quilt's design has seam-lines that will work as registration lines, and that's better yet!
If your project is small, mark all the registration lines before beginning to quilt. On a larger quilt, you may want to mark several, stitch, then go back to mark more. Whatever size project, after marking, go sew along each of your marked lines. Don't stitch exactly on each. But use each line as a general guide, sewing along with a slight wavy motion, crossing the line randomly as you sew. I use my walking foot with a stitch length of 3.0, and my preference is to begin quilting all rows from the same end of the quilt. Honestly, at this point, I nearly always question my judgement on quilting design, but be patient. It's going to look better and better the denser you go.
Once you have quilted along all the registration lines, go back and quilt roughly down the middle of each channel. (indicated by blue stitching) The wavy lines can echo the previous lines in some spots, and move opposite them in others, varying the widths between lines as you go.
Now that you've quilted down all of the channels in the same relaxed, wavy way, go back and do it again. (indicated by green stitching) Eyeball the center as you go, weaving along. Nothing needs to be exact.
At this point, with your quilting about 3/4" - 1" apart, you can decide whether you want to start overlapping some of the quilting. It's all a matter of preference, but it's an option.
You can do a little or alot. And you can overlap most of your lines, none of them, or a mix. It's all up to you. I keep quilting down the channels until the distance between lines in some places is about 1/4".
Let me know if you have any questions! And enjoy some low-stress quilting by going organic!
Also note that fellow FAL co-host Jennie/Clover & Violet had a similar idea as I when planning for tutorial week. Hop over to her blog on January 5 to view her video on Wavy Line Quilting.