I'm not much for following patterns for things such as this, but my favorite way of working up a dishcloth has pretty much become a formal pattern. I tend to make them this way because they work up super fast, have a good "scrubby" texture, and are kind of pretty while still being completely utilitarian. So here goes...
A size H crochet hook
worsted weight cotton yarn (one small ball is exactly enough)
Make 2 DC in 3rd ch from hook. Skip 2 ch, then SC in next ch. *skip 2 ch, 4 DC in next ch, skip 2 ch, SC in next ch.* Repeat ** until end of row. Ch 2, turn.
2 DC in first st (last sc of the last row). SC in the center of the 4DC-cluster (insert hook between the 2nd and 3rd DC). *4DC in next SC. SC in center of the next 4DC-cluster* Repeat ** until end of row. Ch2, turn.
Continue in this pattern until you have completed 20 rows.
At the end of the 20th row, ch 1, turn.
next row: sc in each stitch to corner (29sc). Ch 1. Make 29 sc along each of the remaining 3 sides with one ch in each corner. Then connect to the first sc with a sl st. Ch1, turn.
NOTE: The bottom edge where the beginning foundation chain is contains 33 sts. Just skip a few for a total of 29 sts.
Sc in first st. Ch 3, sl st in the same sp as the sc you just made. *SC in the next 3 sts. Ch 3, sl st in the sam sp as the last sc.* Repeat ** until you've covered all 4 sides. Connect last st to first sc with a sl st. Bind off.
Weave in loose ends.
Now go clean something :-D