Assumptions (unless noted): Seams are 1/4", sewing is done with right sides together, backstitch each time you sew
Supplies: two pieces of fabric large enough to make your bag body, cording (I chose macrame, but ribbon, leather lace, twill tape, etc will work nicely), safety pin, thread, rotary cutter and/or scissors
To figure out the size of your fabric: Take a loose measurement of the item you want your bag to hold. I wanted a ball of yarn, needles and my half finished hat that measured about 8"x8" when I put in on my cutting mat. I added two inches to each side of the measurements to allow for cinching or bigger projects, so my bag sides will be 12"x12"
1 piece bag outer (width equals your project width, length is project length time 2) I cut mine 12"x24"
1 piece bag inner the same size as the outer
2 pieces cording the width of your bag times 3 (mine was 12*3=36")
Step 1: Fold bag pieces in half lengthwise. Measure 1.25" from the top and mark. Measure 1" from that and mark again. Do this on both sides of the bag outer and bag inner. This will be your casing.
Step 2: Sew from the top of the bag down to your first mark. Pick up the needle and sew again from the second mark to the bottom of your bag. Again, do this on both sides of the bag outer and inner.
Step 3: Press seams open making note of holes that were left for casings.
Step 4: Stitch a box around the hole, catching both seams. This is the step that will reinforce the casing so that the ends don't poke out. (White thread used to be visible in photo, use coordinating thread)
Step 4 1/2: From the outside, it will look like this. And, yes, do this for both holes in the lining and bag outer.
Step 5: Turn bag inner right side in, and leave bag outer right side out. Place bag inner inside of bag outer so that the right sides are facing. Make sure that the holes for the casing line up.
Step 6: Stitch along the upper raw edges of the bag. Leave a two inch opening for turning.
Step 7: Turn bag right side out so that the bag outer and bag inner make a long rectangle.
Step 8 (Sorry! No photo): Shove bag inner into bag outer, then press the opening shut and stitch either with your machine (like I did) or blind stitch it closed with a handsewing needle and thread.