Measure the table. Use a tape measure to determine the diameter of the table you're going to cover. Add additional inches to your measurement depending on how far you want the tablecloth to hang from the table. Also add one inch for a hem allowance. Purchase the required amount of fabric in your favorite pattern at any fabric store.
Start sewing. Sew the fabric panels together to create a square, if your tablecloth will be wider than the width of your chosen fabric. The width of the square should match the diameter of the table. Attach additional fabric matching the width of the sides of the table, the portion that will hang, to the center portion. Be sure to keep the seam straight when sewing and use a zigzag pattern for the seam allowance. Use an iron to press out all wrinkles.
Fold the fabric. Take the square fabric piece you have just sewn and fold it in half. The corners should match up perfectly. Fold it again from corner to corner. You will have four pieces that overlap each other.
Create an outline. Starting from the edge of the fabric, measure toward the center and make a mark with fabric chalk to indicate a measurement that is equal to half the diameter of the table you plan to cover. Take a piece of string that is also equal to half the diameter of the table, and attach it to your fabric chalk. Also attach string to fabric on top of the chalk mark you previously made. Begin at the mark you made on the fabric, and stretch the string upward until it is taut. Lightly trace an arc on the fabric.
Cut and hem the fabric. Use scissors to cut around the arc. Use an iron to press a 3/4 inch hem all the way around the fabric. Pin it in place. Use a sewing machine to stitch in the hem removing pins as you go. If you do not have a sewing machine, simply sew the hem by hand with needle and thread. Use an iron to give your tablecloth a final press.