Lures for Spanish mackerel work best with a high speed retrieve, probably because the fast-moving lure resembles a panicked baitfish swimming for it's life. The most popular artificials are usually metal jigs two to three inches long, weighing up to 2 ounces. The color or finish on the lure will vary, but sometimes the macks will show a distinct preference for a certain color. Silver is still a consistent producer, but the color of the lures have changed from silver to a lure with some color. Pink and white is probably the hottest, and there are several other combinations that folks will use.
Gold can also be very good.
On the beach, long casts are often necessary to reach the fish, so the tackle necessary to propel a lure that weighs less than three ounces almost a hundred yards can be fairly specialized. One or two piece, light action, graphite or graphite-composite rods in the 9 to 11 foot range are ideal. The tip should be light, but not too whippy, or most of the power of the cast will be absorbed by the rod. The advantage to graphite is the lightness of the blank, and that is very important when repeated casting and extra distance are involved. I like the white series of Team Daiwa spinning rods, mated with the Daiwa Emblem-X reels.