Always had trouble trying to level this. Was a pure mage, 50+ hours into the game, and my restoration was almost level 40. So, through some experimenting and boredom, I learned a way to easily power level it.

First, do the college of winterhold. Inside Labrynthian, near the entrance, you'll find the 'Equilibrium' spellbook. This basically transfers 25 health into magicka per second. Once done, equip equilibrium in one hand, and fast healing in the other. Then basically hold down equilibrium, and fast heal constantly. As your health is turning into magicka, and your magicka is being used to restore health, its an endless cycle of constant healing, which will end up with you raising your healing pretty quickly. Now, its not at all fast like soul trap spam, but as restoration goes, its probably the best way to level it.

Good idea, will try it with my new char. together with my own way of levelling Restoration which is:
Find a crab, cast Heal on you and cast Courage on the crab. If your magicka goes down, run around and start again. You'll level:
Restoration, Illusion, Light or Heavy Armor pretty fast.
And later when it becomes harder to increase your Restoration and Destruction skills: Take a Troll and cast Flames and Heal Other. But you should be at high level and strong enough to do it.