They usually attack new leaves and buds. Plants infested with mites lose their green color and appear bronzed or washed out. In severe cases, the mites will form a fine webbing covering the underside of leaves. Once a plant is infested with mites, control will be difficult, if not impossible. Isolate your plant immediately, and dip it or spray it weekly with insecticidal soap.
Systemic insecticides are sometimes effective if used soon enough.
This year it was massive. I would try an organic insecticidal soap again, and the next day begin a process of spraying each plant, each day with as strong of a stream of water as you think your plants will withstand, making certain to spray the bottoms of the leaves. Mites can reproduce each 3-7 days, so it is critical that you spray on a daily basis until the problem is under control. Dry air encourages spider mites to breed so anything you can do to increase the surrounding humidity will help you in your 'mite fight'. Keep in mind that spider mites are NOT insects, so insecticides may not do any good at all, so be sure that the product you use is listed as being effective against mites, and follow the directions on the label.