Any cotton yarn is perfect for this dish/wash cloth.

Needle size is whatever you prefer to use with a cotton fiber. I am a loose knitter so I use a smaller needle size to help my picture patterns stand out, usually a US3.

Most cloths will range between 8x8 and 9x9 regardless of the needle size chosen and will use less than 2oz of yarn.

This is a picture cloth so a solid color is suggested to make sure the picture can be seen. Also note that if the color is too dark ie: black, or too bright ie: neon yellow the pattern may now show up as well.