Lay the pattern on a hard surface to determine how much fabric you will need. If the fabric is directional, you might need more fabric. Otherwise, you can flip the pattern so that it uses minimum fabric. Fold the fabric right sides together, lengthwise, and cut through BOTH layers. I used 45" wide fabric (our 100% cotton, quilt quality fabric from our online store). I needed 2.5 yards (this allowed for shrinkage).
NOTE: The straight, double-ended arrow represents straight of grain. The straight of grain contains no stretch. In our example, there is more stretch across the width of the fabric (no stretch along its length). The straight of grain runs the length of the fabric. This means that the arrow must be exactly parallel to the edge of the fabric. Draw your arrow on your pattern so that it is exactly perpendicular to the bottom leg edge. This is how you keep your pattern piece straight on the fabric. Measure the distance from the end of each arrown to the edge of the fabric to be sure yoru pattern piece is straight. Laid out correctly, your finished product will have some stretch across the seat (even non-stretch fabric has some give), and less stretch vertically. This is very important.
Pin the front pieces together at the front center seam, keeping them right sides together. Using a 1/4" seam allowance, stitch the front pieces toggether at the center seam. Repeat with the back pieces.
Lay out your pajama back and pajama front. Pin the front to the back, right sides together, along the outer seam. Using a 1/4" seam allowance, stitch the front to the back at the outer seams.
Pin the front to the back, right sides together, along the inseams. Using a 1/4" seam allowance, stitch the front to the back at the inseams. There are two methods for this. One is to start stitching at the center and stitch down one leg, then stitch down the other leg. The second method is to start at the bottom of one pant leg, stitch up to the center and then on down the other pant leg. Either one works, but if you are a beginner it might be better to use the first method.
Hem Legs & Add Elastic To Waist
Serge or zig-zag around the bottom of each pant leg. Turn under each pant leg 1/4" and press. Turn under 1/4" again and press. Machine stitch around close to folded edge of hem. If you prefer, you can hand stitch the hem rather than machine stitch.
Serge or zig-zag stitch around the raw edge of the waist. Turn under 1/4" and press. Turn under 1" and press. On the BACK of the pants, place two pins approximately 1.5" apart. Stitch around the pants, near the folded edge of the hem, leaving the area between the pins open. Remove pins. You have now created the casing for the waist elastic.
Cut 3/4" elastic 3" shorter than your waist measurement. If the elastic is very stiff, cut it closer to your waist measurement. Make a small mark on each end of the elastic, on the same side. This way, if the elastic turns while you are pulling it through the casing, you will know it. Run a safety pin through one end of the elastic. Use the safety pin to hold onto while you feed the elastic through the casing. Feeling under the fabric, push the safety pin with one hand and pull it with the other until the elastic is all the way around the casing. Be carefuly that the second end of the elastic is not pulled up into the casing.
Remove the safety pin and stitch the two ends of the elastic together by laying one over the top of the other as shown top right (check your marks first to be sure the elastic has not twisted). Stitch securely.
Pull the waist open, stretching the elastic. This will pull the loose, stitched end into the casing. Adjust gathers. Stitch the casing opening closed.