I used a serger for the major parts of the seams to join the front and back of the body piece together. Because the serger cuts as it goes along, there were some parts I couldn't do without cutting into places I still wanted attached.
Finish along the outside of the arms with a regular sewing machine.
Leave the bottom and inside pants seam open.
Trim the bottom and any excess from the arms.
Cut down the middle to separate the leg portions. Be careful you don't cut too deep.