I started out cutting off the top of the kitchen towel to make the aprons short enough for little ones, and create the apron shape. If you were making this for an adult, then you don't need to trim down the top of the towel. You want to create the classic apron shape at the top, by cutting about a 45 degree angle at each side to create the arm holes. You want to have a straight top to the apron, which is approximately ⅓ of the towel, and the angle the sides down to the waist. Mark your pattern with a disappearing maker and cut off the sides.

Next use an iron and the ironing board to fold over the raw edges a ¼ inch seam allowance, and then another ¼ inch to create a nice folded edge. Use straight pins to hold the edge of the towel in place, and sew the edges with a straight stitch using the sewing machine and white thread, or whatever matches your apron.

After the basic apron shaped was sewn, I added on a neck strap, ties for the back, and a little ruffle at the bottom.
To make the neck strap and apron ties I used some pink polka dot ribbon. I sewed it on to the apron and finished the ends with a little fray-stop to ensure the length of ribbon doesn't unravel. Using a pretty ribbon for this part is a cute little apron detail.
We also found ready made pink ruffles at the fabric store. This made adding this detail really easy. I just turned in the raw edges and used a top stitch to add it to the bottom seam.
For the little boys I used cream coloured twill tape for the fabric ties and didn't add the ruffles to the front