These make wonderful gifts and I encourage you to find a brightly coloured, all-cotton yarn. The yarn I used for these was from Egypt and knitted up beautifully. You can make them larger or smaller just by increasing the number of stitches you cast on. And I love the texture of the double moss stitch.
Use needles advised by the yarn you buy. I used 4mm.
Cast on 39 stitches.
Knit six rows.
+ First row:Knit 4 then knit 1/purl 1 until last 4 stitches which you knit
Second row: Knit 4 then purl1/knit1 until last 4 stitches which you knit
Third row: Knit 4 then purl1/knit1 to last 4 stitches which you knit.
Fourth row: Knit 4 then knit 1/purl1 to last 4 stitches which you knit +
From + to + forms the pattern which you repeat until you have nearly made a square. Finish off with another six rows of knit and cast off.