I have a thread rack that I purchased at JoAnn's. I extend the small dowel by inserting half of a straw, making it longer. This way I can put 2 spools on each small dowel.
Also for my bobbins that I constantly use, I put them on an old "ribbon maker". It has about 12 spools (spokes). I fill my bobbins and keep them close at hand so I don't have to keep winding bobbins. Natural is my favorite color thread and wind a bunch at a time. As for other assorted bobbins, they're in a bobbin case until I need that particular color. Hope that helps.