Worked from the top down, you can try these on as you go, making sure that your shaping is matching your body. They are also a great project for using up leftover skeins of yarn, giving you the option of some wildly striped leggings.

These long johns are easy to custom fit to any size, as long as you get gauge.

Size 6, 24 inch circular needle
Size 6, 16 inch circular needle

5 sts to the inch, in stockinette st in the round
To save time, take time to get gauge

5-10 skeins of yarn are needed, depending on your size, and the length you choose to knit.