First, there is a big difference between black and yellow cardamom. The yellow cardamom is the fragrant variety; black cardamom is smoky. Yellow cardamom is used in many of my spice recipes.
I buy the whole yellow cardamom pods and husk them to remove the seeds as I need them. The pods protect the seeds against air and light, keeping their flavour longer. To husk, place the pods in a paper towel pocket and smash with flat end of meat tenderizer tool for easy hulling of seeds. A garlic press will also crush the pod, but it is not as easy to grab the pods. Once the husk is crushed, it is easy to separate the seeds. Paper towel helps the seeds from rolling everywhere.
As with many seeds and nuts, toasting the seeds before grinding boosts the flavour. Put cardamom in a small, dry skillet over medium-low heat. Shake until the aroma is released, then immediately grind for use. Don’t leave in the heated skillet to prevent over roasting of the seeds.