I love reversible bags, and I had never seen a reversible drawstring bag before, so I decided to sew one. :) And no visible side seams!

Because it's reversible, I recommend working with two different fabrics, so you can later decide which pattern or colour fits better to your mood or outfit.

The sewing needs a little practice, but it's really not difficult. I mean, if you can use the sewing machine, you can do it.

Step 1: What You Will Need

two different fabrics (or three - two for the "outsides" and one for the inner pockets, if you want them plain like I do)
scissors
2 zippers (18cm/7inch)
measuring tape or ruler
pins
sewing machine
1. thread
2. universal/zigzag & zipper presser feet
4 meters/160 inches of cord
rotary cutter (optional)
2 carabiener clips/carabine-swivels or idontknowwhattheyarecalled

Step 2: Cut

Fabric:

Bag: 35x50cm/ 14x20 inch - two pieces from each fabric
String tube: 35x5cm/ 14x2inch - two pieces from each fabric
For the pockets: 21x21cm/ 8,5x8,5 inch - four pieces (two for each pocket)

Cord:

4pcs: 10cm/4inch
2pcs: 180cm/

Step 3: Pocket - Mark and Sew

Mark a rectangle on the top of the pocket-fabric: 1x18cm/ 3/8x7inch, leaving 1,5cm/ 5/8inch by the sides. I made a paper stencil, so it was easier to do.

Put the small piece (the pocket) in the middle of the big (the bag) one. Right sides facing up. Find the centers easily without measuring: folding them twice in half.

Pin the two pieces together and sew where you marked.

Step 4: Pocket - Clip and Turn

Clip inside the marking as showed in the picture.

Flip the pocket piece to the other side and pin.

Step 5: Pocket - Add the Zipper

Place the zipper in the hole you pinned, pin again and sew.

Pay attention to the corners - only lift the foot while the needle is down.

Step 6: Pocket - Finish

Cut off the excess of the zipper.

Place the back of the pocket onto the front (wrong side up) and sew.

The pocket is done!

Do these steps again with the other fabric.

Step 7: Sew Together

Place the big pieces of the fabrics on top of each other.

Order:

fabric 1 with pocket, right side up
fabric 1 wihtout pocket, wrong side up
fabric 2 with pocket, right side up
fabric 2 wihtout pocket, wrong side up

Sew the layers together. (Do not sew the top.) Leave about 3-4cm/ 1 and a half inch by the corners.

Step 8: Sew the Cord

Fold two 10cm/ 4inch cords in half and put in the corner between the layers of fabrics. (The pictures will explain better.) Make sure they don't move. Sew. I recommend backstiching over the cords. Cut down the excess.

Do this with the other corner.

Step 9: Prepare the "tube"

Sew one longer side of two 35x5cm/ 14x2inch pieces of fabric together (right sides facing together). (Though I used these "fancy" stiches as seen in the picture, you can use straight and zigzag stich as well.)

Open, fold the ends twice and sew down.

Fold in half along the long stiching - wrong sides together. Pin (it's not necessary if the fabrics are stiff enough to stay more or less together).

Step 10: Prepare the Top

Sew the same kinds of fabric together on the top (where I told you not to sew).

Turn the bag (I think we can say it's a bag now) inside out, treating tree layers as one. If one of your fabrics is softer than the other, that should be outside.

Step 11: Sew on the "tube"

Pin and sew the long folded "tube" on the outer fabric.

Fold down the seam allowance of the inner fabric and sew just above the stiching you have just made.

Step 12: Slip the Cord Into the Tube

It's easy with a safety pin. Slip the cords through both tubes, starting on opposite sides.

Tie a duble knot on each cord. Make it as small as you can. If you have non-flammable cord (like I do), you can carefully put the knots above fire to ensure that they will not come apart easily.

The knots should be in the ends of the tubes.

Close up the bag, find the cords' half, attach the carabiener thing and tie another knot to keep it there.

Step 13: Done!

Yess!

It might seem a little complicated, but if you go through all the steps and understand them, it won't be difficult. I'm sure you can do it - I could too, and I'm only 15.

Good luck!