Give it the Exp. Share and fight not only the Elite Four, but Morimoto (In Castelia City postgame), Cheren, Bianca (when possible), Audinos, the Nimbasa City Domes, and Cynthia when she comes back. I have used this to get 14 lv. 100s (including volcarona and a SHUCKLE) and I get more daily. Hope this helps. P.S. and when its strong enough, you will kill EVERYTHING!