Sashiko kits are available online. I got mine at the New England Quilt Museum and the City Quilter. I bought the thread and needles, and that is all one needs. The blue fabric is marked with stitching guides that wash out. I kept poking myself as I loaded many stitches onto my needle so I bought some stick-on thimbles. After wearing one, I found I never stuck myself again. I find it easy to pull the thread through, but people also use wider rubber bands or finger protectors from the drug store to pull the loaded needles through the fabric.
When I first got interested in Sashiko, I bought books and tools to print my own designs on navy fabric. Ellen showed me the beauty of the colored threads and how to start and end without knots. There are preferred paths to follow when stitching, but it is not imperative.
I picked up 12" x 12" pillow forms at JoAnn's half price last week. Needle-pointing coasters and knitting are great travel crafts, but Sashiko coasters are a new one for me. Click to enlarge the photos to see mistakes that happen when you hit potholes or before one learns all the rules! In all honesty, I take out my stitches a lot so it may not be so easy for children. I believe perfection doesn't happen for me, even in easy tasks.