Walk. A lot. That's what I did to have my Riolu evolve into Lucario. Got the egg. Went from Twinleaf to Eterna City. Explored the Old Chateau. Trained other Pokemon. Riolu got to about level 16 from Exp. Share. Traveled across all of Sinnoh. Finally evolved in probably less than an hour. Just get on your bike and go across the region. It's a little bit time consuming, but it's kind of fun. It's not that bad, really. Especially if you have that pedometer on your Poketch; then you can actually see your work. Haha. 256 steps is plus one happiness.
Giving vitamins (Protein, Calcium, etc.) also help if you have the money. If you're worried about EVs, then make sure you count them, y'know. Oh yeah, definitely get it a massage or two. And don't let it faint, so use the Exp. Share to get some levels if Togepi is low-leveled. Gaining levels also add happiness points.