While playing through my first time, the only alteration spell I ever used was Candlelight to see into some of the more dark corners of dungeons. I noticed, however, that my alteration skill never went up from it's use.

So now I am playing a Ninja (stealth, 1h, illusion) and I desperately need to raise my illusion. Will just using clairvoyance raise it? Or will I need to use the targeted spells to actually raise the skill?

Fear does it for me

Get "Detect Life" ASAP. This is by far the best spell for raising illusion as you can safely cast it in town when you're on your way to sell or turn in quests. When first raising it, it can raise a level with 1-2 casts.

I thought Detect Life was alteration ?

Just use Courage on NPCs in town, or constantly cast Muffle

Detect life is alteration not illusion -_-.

Muffle I find works best for illusion, it's useful too!

muffle is the spell to train for illusion. It levels the skill very quickly and does not require a combat situation.

yes. spam muffle for the quickest way to boost illusion.. FACT.

This.

I guess I should buy muffle then, if that will work.

So I take it to mean that clairvoyance doesn't do [censored]?

probably not,sinces its a guide spell they probably figured a lot of people would use it constantly and if it kept leveling up illusion it would screw up the scaling and what not