Fun with Saffron
Saffron is tremendously expensive. When you buy it, you should get the most of it that you can.
When shopping for saffron, look for evenly colored, vivid red or deep orange threads. Lighter colored threads or a lot of pale streaks indicate lesser quality. Avoid powdered saffron, which is always cheaper but often inferior and adulterated with other flavourings.
Crush and soak saffron to release its flavor. Saffron threads are quite frail and can easily be crumbled between your fingers, although for a more uniform powder, use a surabachi or a mortar and pestle. Measure (or count) saffron threads before crushing. A "pinch" is about 20 medium saffron threads.
Saffron needs moisture to release its flavour. The best way to do this is to soak the threads in hot (but never boiling) liquid for 5 to 20 minutes. Then add both the saffron and the liquid to the recipe. As the saffron soaks, you'll notice the distinctive aroma indicating that your saffron "tea" is ready. It's nice soak the saffron in stock or wine (rather than water) to add to the overall flavour of a dish.
When adding saffron to soups, stews, salad dressings, and other recipes with a lot of liquid, you can simply toss the crushed threads in with the rest of the ingredients. But you will get a deeper, more pervasive saffron flavour by first soaking the crushed threads and then adding them.
For traditional paella recipes, cooks first toast the saffron threads in a dry skillet to bring out the volatile oils. I don't think that this step makes much difference in the final flavour of the dish.