Here's how to make a GREAT reversible bag! I got the pattern here from Very Purple Person . Just print it off and tape it together...then cut it out. You'll need 2 contrasting fabrics for ultimate cuteness. (I didn't sew in any darts...) Cut 2 of each fabric on the fold to make this shape. Put the right sides together of each fabric and sew the rounded edge... I zig-zag the edge to prevent fraying. Do that to both...like this Take 1 of the fabrics and turn it right side out. Then fit that one inside the other one...this way the "rightsides" are together. Line it up straight... Now you are going to sew the 2 layers together. Around the "neckline" and the "armpits" and the "backline" Leave the top 3 inches of the straps unsewn. Then cut little snips around the rounded edges. Take care not to cut the stitches. This will allow the fabric to lay flat inside that rounded edge. Like this....