You could use an overlocker or a machine zigzag stitch to finish the raw edges of the seams on woven fabrics. The items in this book are small ones that are not going to be washed, so this is optional. Because of the nature of felt and boiled wool, the edges do not need to be finished.
You will find that some fabrics fray more easily than others – for example, velvet and essian. Using a product such as Fraystop will help.