I go to a thrift store or yard sale, find a used table cloth of the correct size and shape. I make my top, square or rectangle, and then using the used cloth as backing, I birth a new table cloth. This is an easy way to make that round or oval cloth. I don't use any batting and quilt the new cloth ever which way seems best.

I made a tablecloth and used the insulated batting so that I could put hot pans on it. I also make them and my tablerunners two sided. Like for Thanksgiving I have fall colors and on the other side I make the same design but use Christmas colors. It works great and it cuts down storage space; like 2 for 1.

I have a quilt I use as a tablecloth. Were I to make another, I would make bigger, simple blocks and a wider border where plates, cups, etc. go. Reason being that we've had some spills because cups were on the seams.

the advantage to using a flat batting (eg., warm and natural or w & white) instead of a flannel is that the batting will let the seam allowances sink in and the top will not be a "bumpy" ...but stability of cups and glasses will still be a problem. One way to "piece" a block is to just overlap the seams and use decorative stitches to do the quilting and stitch the pieces together at the same time.In this case, a flannel center would be fine since there would not be the traditional bulk of seam allowances. A single, very large block, might be practical, especially if you use something like a star where the covering can be adjusted so that individual places for eaters can be positioned between the star blocks....or how about appliqueing placemats to the perimeter with only the very center as an actual block...

If you have a really nice pieced tablecloth, one possibility would be to have a piece of glass cut to match the table top. Then you'd only have to worry about spills over the edge.

I have made several tablecloths for my round table. I like to have seasonal ones, also I make a tablerunner to match for my buffet. I have made them with nothing inside and with W&N batting inside and I like the batting best. I make a large square that fits over it and drapes well. We do not eat on it, just remove it.

When I made my Christmas wreath tablecloth, I made a square for a round table and did as you said. Just big enough to drape over the edges. But we ate on mine.

This is quite encouraging. I've made a tablecloth for Christmas when the table is pulled out full length. The design defines the place settings. Many of the challenges with this cloth have been addressed here:
How to make glasses stable with the uneven thickness at seams.
How to minimize stains and washing
What to use as backing
I'm thinking I'll finish it as a quilt and hang it on the wall, maybe, maybe not.
Hoping it'll be finished for use by next Christmas, it's only been 5 yrs so far.

Here's the picture[ATTACH=CONFIG]399833[/ATTACH]The cloth is big enough for 12 people, but designed for 8. It's really pretty with my poinsetia china and table decorated with silk poinsetia and candles. Very elegant.

I have made table clothes like quilts and I use felt in the middle and it turns out real nice. Felt come in 60 wide on the bolt. Have a great time.