i need help leveling destruction as fast as possiable, as my save file will become very laggy quite soon, and id like to enjoy some killing befor it does, any tips would be helpful, i also want to avoid ash piles so any tips that dont make ash piles would be even more helpful.

Get the Shadowmere horse from the Dark Brotherhood quest line. Enchant four pieces of equipment that reduce your destruction cost to zero. Equip one of the low level destruction spells like flames or sparks and begin shooting Shadowmere with the spell. Wrap a rubber band around the controller so that the spell will continue to shoot indefinately. Go to bed. When you wake up you will have 100 destruction.

I haven't done the DB quest yet so please be patient with this question. Why is the Shadowmere mount important for this? Is it immune to destructive magic?

I think it's healing rate is faster than the damage rate of the spell? ...and quit asking such dumb questions!

Shadowmere is virtually immortal. It can take pretty much anything you throw at it.

The perfect sparring partner.

Just wait for the patch and you won't have to power level anything. I advise not to power level. In the later stages of the game it may hurt you. I did it for smithing and block and I really regret it.

If you still decide you want to do it then you'll need 100 in enchanting with the middle row or perks filled up. You need 25% on you helmet, armor, a ring and necklace, once you reach a total of 100% destruction or whatever other type of magic you choose will cost nothing. This is how I made a full transition on level 60 from a theif/warrior to a destruction Mage.

Thanks for the answer!