Not sure if someone has already discovered this,if so then apologies in advance
Head to Halted Stream camp near Whiterun and clear out all the bandits.Then take the rear exit door that opens out at the base of a pit filled with wooden stakes sticking out the ground.Save your game.Now all you have to do is deliberately run into the wooden stakes 2/3 times,leaving a small fraction of health left.Simply heal yourself an keep repeating this process till your bored of it basically you can increase your restoration levels rapidly doing this,and you won`t get interupted either.Enjoy

Thanks for the tip! I can just imagine my character running head first into some wooden stakes ...

or you could use equilibrium, then heal til your health is back and repeat..

Are you trying to get all the dragonborns to commit suicide? You're really working Alduin, aren't you?

Or, you could just jump in and out of a forge.

i also know one the the spell that adds mana and removes health you do that and heal everywhere

What kind of masochist impales them selves on wooden stakes only to heal them selves so they can be impaled more? I guess the same kind that drains their life force only to restore it back so they can drain it again. And the person that jumped off of rocks in Oblivion and shattered his legs only to heal them again and repeat the process (me).

Or if you also want to increase an armor skill while you do it just find a few enemies(like legion/stormcloak soldiers or bandits) and let them hit you as you heal yourself. One of many ways to grind if you are interested. Me, not so much, though I have done it before.

That spell is called Equilibrium, like whiteguy1x said

I tried using that spell after learning it ... My mage died beside Alduin's wall

Or stand in the blade traps in bleak falls borrow. Or stand in a fire... or stand in the cold winds at the throat of the world... or let two frost trolls repeatedly hit you in the face... or...

Just cast equilibrium, it is by far the fastest way to level restoration.

Thanks for all the replies so far guys.Its amazing the variety of ways we all have of levelling up our skills I may try jumping in an out the forge lol.