We used transfer (red) pencils to trace the designs from coloring books and ironed on to white fabric. We then iron freezer paper to the back of the square to stabilize it for coloring. After all coloring, and we used plain old crayola, we ironed the square with a piece of wax paper, face down on the coloring. It seemed to set it better. Used laundry markers, cheaper than fabric markers. Kids used to do them at sleep overs, and then they would sign them. I would put them in lap quilts and they loved to see their pictures when they came back over. After doing our squares this way, we have washed these many times, at least once a week for 7 years now, and they have held up well. We did find the harder they pressed and the darker the color, the longer it held up. But I like the look of the faded colors, more vintage.