Here's how I made it: I started by prewashing my fabric, ironing it, and laying it out on the floor to mark my sewing lines.
I then took an old tablecloth purchased a number of years ago and placed it over the top of my fabric so I could "draw" my sewing lines. Before layering in this fashion I did mark the center of my fabric and the center of my existing tablecloth by folding each in fourths and using a pin to mark the center. Then I matched and pinned the centers when I layered them. It then looked like this: (See how the fabric is not quite as wide as it really should be? Oh well, it can't be helped.
I simply traced around the tablecloth with a washable fabric marker. I did not leave much of a seam allowance (only about 1/4") because I knew I would finish the edges on my serger with a rolled hem. My tracing lines looked like this:
Here is a close-up of the rolled hem:
Some time ago I made a table runner using the same line of fabric (100% quilting fabric, no linen) and it looks great on top of my table with my new tablecloth.