Here's the pattern I like to use for dish rags from
here.
Size 7 or 8 needles
Worsted weight cotton, less than 1 ball
K = Knit
P = Purl
K2tog = Knit two stitches together
K2tog tbl = Knit two stitches together through back loop.
Inc = Knit in front and back of same stitch
Cast on 3 stitches.
Increasing Half:
Row 1: knit
Row 2: K1, inc, k1. (4 sts)
Row 3: Knit
Row 4: K1, inc in next 2 sts, k1. (6 sts)
Row 5: Knit
Row 6, 7, & 8: K3, yo, knit to end. (7, 8, & 9 sts)
Row 9: K3, yo, k1, purl to last 4 sts, k4. (10 sts)
Repeat Rows 6, 7, 8, & 9 until the cloth is your desired width, ending with Row 9.
Corners: (I use short rows for a neater corner. If you do not wish to make your corners this way, I put the short row corner in brackets, so you can eliminate that portion and just do the row as written.)
Row 1: {K3, turn; sl 1 st, k2, turn; k2, turn; sl 1 st, k1, turn; k2, turn, sl 1 st, k1, turn; k3, turn; sl 1 st, k2, turn}; k2, k2tog tbl, yo, k2tog tbl, knit to end.
Row 2: Repeat Row 1.
Decreasing half:
Row 1: K2, k2tog tbl, yo, k2tog tbl, knit to end.
Row 2: K2, k2tog tbl, yo, k2tog tbl, purl to last 4 sts on needle, k4.
Rows 3 & 4: Repeat Row 1.
Repeat Rows 1, 2, 3, & 4 until you have 7 stitches left on your needle.
Row 1: Knit.
Row 2: K1, k2tog tbl, k1, k2tog, k1
Row 3: Knit
Row 4: Bind off, knitting last 2 sts tog before binding them off.
I had these all rolled in a bundle to give someone and they won't lie flat now, so I folded them in half for the pictures. :D