To reduce a sauce, remove any solids such as meat, vegetables, fruit or herbs from broth by straining. Return to pan. It works best if the pan is wide and shallow. And it is best if you have about twice as much broth as needed. Simmer over medium high heat until volume reduces by 1/3 to ½. This will thicken sauce and intensify the flavor. If it is not thick enough for you at this point add a little arrowroot mixed with a small amount of water. Make sure you do not season with salt until end of reduction. Salt also intensifies as you cook it.