Go shopping with a friend who has an amazing ability to spot cute fabric from 3 aisles over. Buy 3 yards of it.
Buy a pattern for Jammie pants. I prefer to ones that market themselves with the words "easy" or "simple." Try not to judge them based on the models or you may leave the store without a pattern.
Cut out the 2 pattern pieces needed. One is for the back and one is for the front of the pants.
Fold your fabric in half before you cut it. You need to cut 2 of each since you have 2 legs. If you only have 1 leg, you can skip the fabric folding step.
Cut out the fabric along the pattern lines.
Match a front leg piece up to a back leg piece for the left and right legs. Make sure the cute side of the fabric is on the inside.
Thread your sewing machine with a color thread that matches your fabric. I'm using pink in the bobbin and white on top.
Sew a straight stitch down the inner leg on both legs.
Once you've sewn the inner leg seam, you are ready to sew the *ahem* crotch seam. (Is there a more ladylike word for that?)
Matching up the 2 seams you just made, place the back of the Jammie pants onto the front with the cute side of the fabric on the inside.
The pattern suggests reinforcing this seam, so I sewed it all the way from front to back once, and now I'm doing another shorter stitch over that one to make it stronger (Less likely to get a hole).
Once that seam is completed, it's time to sew the outer leg seams. But first, we need to turn the pants a bit so they're back in an inside-out pants shape.
Once you have your pants turned the right way, sew 2 long straight stitches up both sides.
Now you can turn your jammies right side out. There's only 2 more things to do. Hem the bottom and put in the waistband.
To sew the waistband, I fold the fabric over twice and sew. The first fold is small (a quarter to half an inch) and the second fold is larger (an inch).
When you get to a seam, fold it flat as shown.
When you've almost sewn all the way around the waist circumference, stop an inch before you meet the start of your seam.
Measure a piece of elastic to the size of your waist (or the size of the waist of the lucky recipient of the jammie pants).
Pin a safety pin to one end of the elastic.
Insert the safety pin into the 1 inch hole that you left when you sewed the waist. Feed the safety pin through the waistband all the way until you get back to the hole on the other side.
Once your safety pin makes it out the other side, you can remove it from the elastic and sew the two ends of elastic together tightly.
Once the elastic is sewn together, you can tuck it into the waistband, and stitch up the rest of the seam.
The final step is to hem the ends of the legs. I do this the same way as the waistband. I fold over the edge twice and stitch.
All done. Jammie pants in one night. Snowmen painted toenails are sold separately.