Instructions
Choose the fabric. Only a few are suitable for the delicate newborn's skin. Cotton flannel, lightweight fleece and soft knitted jersey are the best choices. They are soft, absorbent and can withstand many washings and dryings.
Decide how you want to make the bassinet bedding. Buy patterns, available at most fabric stores, which also sell crib sheets, blankets, bibs and other accessories for the nursery. If you only are interested in bassinet bedding, you can sew your own without purchasing a pattern.
Measure your bassinet pad. Measure the length and add twice the mattress depth plus 8 inches. Then measure the width and add twice the mattress depth plus 8 inches. Cut the fabric to this size for the sheet. The width of the sheet should be on the crosswise grain of the fabric so it will have the greatest amount of stretch.
Make a square template (cardboard or poster board will work) that is the same measurement of the depth as the mattress plus 4-inches. Use this template to cut a square from each corner of the fabric.
Form the boxed edges that will fit over the corners of the mattress. On each corner where you cut out the square, join the edges with the right sides together. Stitch a ¼-inch seam using your serger or the zigzag setting on your sewing machine.
Cut 2 pieces of ¼-inch elastic 3 inches longer than the width of the mattress. Mark the center of each strip. With the wrong side of the short end of the sheet facing you, pin the center of the elastic to the center of the end of the sheet. Pin the ends of the elastic 6 inches down past the corner seam on each side.
Sew the elastic in place with your sewing machine set on a zigzag stitch or your serger. Stretch the elastic between the pins to make it fit as you sew. If you use the serger, don't cut the elastic with the blades. Continue to zigzag or serge all the way around the sheet to finish the edge before hemming it. Finally, turn under a ¼-inch hem around the sheet, including the section where the elastic is, and sew around, encasing the elastic in the hem.