NOTE: Read all these notes before attempting the actual sewing. The instructions below are for a dorset bag with the pockets on the OUTSIDE of the bag.
Take a 20" x 20" square piece of fabric and a piece of the same size for the lining. For the bag to come out properly, it must be kept SQUARE. A crisp material is better than a softer one.
HOW TO YOU KNOW IF YOUR PIECE IS SQUARE? Fold it diagonally (see image) one way and match your corner and side seams, and repeat on the other side. If all edges and corners match up, proceed; if not, find a straight edge and trim if possible or start with a new piece.
If you want embroidered corners, do that now.
note: if you want your pockets on the inside, embroider on the lining side.
NOTE: If you want extra pockets on the inside of your bag, cut a separate piece of fabric 10" x 20". Finish long edges and fold in half (folded size 5 x 20). Match center seam to center of lining and sew to right side of lining fabric, with the right side facing out.
Sew the lining and outer material together, right sides together, leaving a small opening on one side so that you can turn the square right side out.
Turn right side out.
Press the square flat, making sure you keep it exactly square.
Hand sew opening. Press again.
Place square on table with right side down. Fold square into thirds, folding non-embroidered points over each other on the square, Pin folded layers together without catching bottom layer
NOTE: At this stage you must keep the bag hollow like a tube down the middle; the only complete sewn together seam is across the middle which will be the bottom of the bag and sewn after the other seams, but before the side seams and casing. The embroidered flaps are not sewn down.....they make extra pockets for the bag.
Sew seams along the edges indicated by the blue lines on the above diagram, making sure you are keeping the bag hollow. Sew slowly, using the free-arm option of your machine (if you have one)
Fold embroidered flap over and pin. Sew 1/2" from folded edge to form casing for drawstrings. Repeat for other side.
Press bag and seams flat.
Fold to find center of bag and mark. Flatten and sew through all layers.
Fold bag in half, matching casing seams, pinning to secure. Sew along sides through all layers, starting at casing seam and ending at bottom seam. Repeat on other side.
Thread one drawstring going one way around and the other going the opposite way around tie both ends together.