The first part of this is, of course, pointy ears (I'm rather fond of the Woochie brand latex ear-tips, available for about $10 at most costume shops, pick up spirit gum to attach them while you are there.) The second part is your Elf Stone, for a Wild Elf you will need a yellow one. You can pick up flat backed fake jewels at any craft shop and most fabric stores, then use spirit gum to affix one to your forehead.
On to clothing; Wild Elves most often wear woolen clothing. Kilts are more common than trousers. Though these are patterned frequently in plaids similar to those the dwarves wear these patterns have more to do with what dyes were available than identification of any kind.
Hair is frequently long and worn either loose or partly braided. Warriors are also frequently heavily tattooed (WATER-WASHABLE markers are good for this), show ritual scarification, or both.
Armor is extreamly uncommon amoung the Wild Elves, and they favor larger, heavier swords and spears than do their Forest Elf cousins (who have less open ground to work with). It is not uncommon for a Wild Elf's sword to be nearly as tall as he is.
Jewelry tends to be close chokers and snug bracelets rather than rattling chains and is worn by both men and women. Boots are the favored footwear for these elves as well; though during the summer sandals are more common.