Say that five times fast.
Sarongs (aka pareo, aka many other things) are pretty simple to sew for yourself. You need a solid piece of cloth (light cotton works well) wide enough to cover you, armpit to knee (or longer) and long enough to wrap around your body (not too tightly) one and a half times. You want it to cover you as well as have some overlap, so it stays shut.
So, you’ve got your fabric. (Mine was about 5 feet high by oh, 10 feet? Not an exact science, here. Mine is extra huge, because I measured generously when making it.)
After measuring, cut your fabric. Using a scrap piece, test the tension on your machine. Sew a swatch of the fabric, double or triple thickness, and look at both sides of your swatch. Are there loops of thread? Tighten the tension. Is there puckering and tightness in your threads? Loosen the tension.
All right, start your engines!
I would recommend against hand-sewing this. It’ll go on forever as it is.
I kept the selvage on my piece of fabric, since it actually looked nice and I was using the full width of a bolt. Doing so is an affront to the ladies who taught me about fabric and sewing, (and as such, I am ashamed) but, hey. It works. The only real sewing here is to sew the cut edges (rolled hem is best for a thin fabric, as a sarong ought to be made with.) Just keep it straight, and keep your tension regular.
Have fun with your new sarong! A lot of people love them for beach covers, but since mine is so long, I love wearing it over a shirt as a more comfortable dress for semi formal settings. Whenever I’m dragging my feet to get out of my pajamas on a Sunday morning, my sarong is a nice choice.