Arrange all of your different sewing thread in a handy thread organiser. Use a variety of boxes to hold all of your embroidery and cross-stitch thread, whether on a spool or wrapped around a board spool. A variety of sizes are available, including small travel organisers and larger versions.
Make sure any box you choose securely holds your various spools. Also learn the difference between the many types so that you pick the thread organiser that best fits your needs.