Lay out the fabric and trim off the selvage edges. Be sure to trim the cut edges along the width of the fabric so they are straight.
Fold fabric in half matching selvage edges.
Cut across the full width of the fabric a 4″ length for the strap. Strap will measure 4″ x 42″
Cut the remaining 14″ length of fabric into 4 pieces each 11″ wide. 2 for bag, a 2 for the lining.
Lay fabric for bag with right sides facing and sew 1/4″ seam along both long sides, and the shorter bottom edge.
Straps: Open out the 4″ x 42″ strap fabric and fold in half along the full 42″ width and press.
Bring the outer edge to the center fold and press, do again for the opposite long side edge.
Fold the strip again along the center fold, matching the outer folds, and press.
Sew close to the edges of the strap up one side and down the other.
You can either trim the strap to fit your child, or leave it long to use for a cross-over strap.
Bag: Turn one of the bags right side out. Pin each end of the strap at the top of the side seams, being careful not to twist the strap.
Place this bag inside the other bag and match the side seams, pinning along the top edge of the bag.
Measure a 4″ portion along the top edge. You will leave this portion open for turning the bag right side out. Sew 1/2″ seam around the top of the bag, sewing back and forth a couple of times over each strap, and back tacking at beginning and end of seam.
Carefully, reach through the 4″ opening and grasp the corners of the inner bag and pull through the opening, do the same with the other part of the bag. Press the bag’s top seam, pressing the seam allowance of the opening to the inside. Top stitch close to the edge around the top of the bag.
Cut out felt shapes or letters and glue to the outside of the bag using a good fabric glue such as Tacky Glue.