When you decide that you want to cut down on your household's contribution to the landfills, start by taking a look at what paper products you use the most of. At our house, we used a lot of paper napkins. By using cloth napkins, we cut down on our paper waste and just toss dirtied napkins onto the mountain of laundry.
When it comes to selecting fabric, I do have a couple of pointers. Be sure that it's something that will wash up well and not be too wrinkly. You do not want to be ironing your napkins. Yuck! (Have I mentioned that I hate to iron?) Also, be sure that your fabric looks basically the same on both sides. If you select a print that is mostly white on the back, your resulting napkins will look funny. And, lastly, I love to use the now popular batik-type prints because they don't show stains. Oil stains that won't come out just look like a part of the pattern.
Napkins can be made in any size square you are comfortable with. The standard sizes are 12, 14, and 16 inch squares. The easiest way to make sure they will all be square is to make a poster board template.
Press under all edges 1/4". Press that edge under again.
Using your pressing lines as a guide, trim off the outside corner.
Press the new "corner" down to the inside press line. Re press the first press of the edges.
Press edges under again making corner meet diagonally in center of the corner.
Top stitch the hem into place, swiveling the material as you reach the corners.