Sometimes I like to get fancy with my dishcloths, but when I'm looking for basic, this is the pattern to which I turn.
Crochet Hook Size G
Row 1: Hdc in 3rd ch from hook and all across. Ch 2, turn.
Row 2: Hdc in each hdc across.
Repeat Row 2 eleven times, until you have 13 rows total. Finish off.
Go around your square one or two times with sc, shooting for 18sc on each side, with 3 scs in each corner.