pair it with alteration and restoration. duel cast whatever destruction spell would be most effective for that certain enemy.
frost for melee, shock for mages and fire for everything else (unless its fire resistant). make sure you have a follower to keep the enemies occupied while you blast them. you could also put perks in conjuration to have an atronauch with you as well. if you cant get away from an enemy hold up a ward and use the other hand to cast.
up your enchanting and put some badass enchants on plain clothes and pair that with mage armor from alteration (thats what i do, anyway)
do the mages college early on as well. the benefits/gear/spells is worth it. the dark brotherhood also has decent mages gear.
right now im making my own vampire kit lol...dark elf, vampirism, some alteration and restoration, necromancy, illusion, sneak, enchanting and alchemy. i wonder how itll pan out.