Could someone please tell me a good size to make a mug rug? Square or rectangle?

you can make it any size that suits you. they are usually big enough for a mug and a snack.. or room for your stirring spoon

I made my first ones about 8 x 11" and am liking them that size. They are just big enough for a mug and a small cookie plate! http://www.quiltingboard.com/t-155480-1.htm

You can make them in various shapes and sizes. If you have specific people in mind to give them to the size and shape can be predicated on whether they drink coffee with nothing - no need for spoon space, or do they have a snack - large as an apple or small as a single cookie (I do think there are people out there who can eat just one, never actually met one though). I have made them in square, rectangle and circle.

I have been making mine 6x9 or 7x10. Both those
sizes has been a favorite for everyone I have
given them too.

There's several tutorials on here on different shapes and sizes.

I need to make some, everyone I have seen are gorgeous.

lots of them are the size of basic coasters- since that's really what they are- you can make them any size/shape you want- but if you want to be able to set a cup on them i would measure the cup base and add a couple inches to give a bit of room around the cup.

I usually don't stick to a set size, total rule breaker. Mine about usually 8x8. I havea large coffee mug and like to put my snack plate on there as well, almost a mini place mat. My desktop is glass though so I don't like having much set directly on the glass.

Depends on how big the cookie is. If it's big enough, I could settle for just one.hehe
I have seen 6x9 alot. i think the ones with a pocket for the spoon is cute too. Some make a napkins to match.

I make mine 6x9.