One of my favorite type of pants to sew are one seam pants. I have a tried and true pattern for my little girls that I made years ago by taking apart a pair of pants, tracing and adjusting until I came up with this:
I spent a while experimenting until I got a shape I liked and a pant which fit my girlies well. But there are many one seam pants patterns commercially available (which I found after the fact!)
Since I’m using a really stretchy polar fleece, I wasn’t concerned about the bit of pattern that didn’t fit on the fabric. I’m making two pairs of these is the just about the same size so I’m cheating by cutting them all at once.
Next I sewed (serged) the inseam of each leg. Note that you can tell the back from the front quite easily.
Next take one leg and turn it to the right side. You’ll have one leg where the wrong side is facing out and the other the right side will be facing out
Then put the right side leg into the wrong side leg and match up the center.
Sew the center, turn everything to the right side—you have a pair of pants!
I just fold down the waist about 2 inches to the wrong side, sew and pull elastic through (the elastic still needs to be done)