To sew a new pair of pants, trace a current pair of pants onto a large sheet of paper for the pattern, use the pattern to cut the new pants from the chosen fabric and sew the pieces together. Be sure to use a pair of pants that fit comfortably for the pattern so the new pants have an accurate fit.
Making a simple pair of pants only requires a few supplies. Get a large sheet of butcher paper for the pattern, fabric for the new pants, 2-inch wide elastic and basic sewing supplies.
Step 1: Make the pattern
Fold a comfortable pair of pants in half and lay it on the butcher paper. Trace around the pants, about a half-inch outside of the legs and about 2 inches outside the waist and hem. This is for the seam allowance. Cut out the pattern.
Step 2: Cut the pants
Fold the fabric in half, lay the flat side of the pattern along the fold, and cut along the pattern. Repeat for the other leg.
Step 3: Sew the pants
Unfold the two pieces from Step 2 and lay them together, wrong side out. Pin the inseams and sew both sides, meeting at the crotch. Fold the waist down and make a pocket through which the elastic will be threaded. Finally, hem the legs and sew in place.