[Easiest way to level up illusion]

If you're going to cheat, just use a console command..

eh it's useful for people on console

[Easiest way to level up illusion]

How to quickly level up your illusion:

 

Go to a stormcloak camp, kill all the stormcloaks and then calm the leader i definately do know his name and go to the three injured stormcloaks. You will need two spells like Rally and Frenzy that have an area of effect. Keep spamming the middle of the tent and you will get to 100 in under half an hour.

 

Let me know if it works :D

 

PS: to level it up quicker put the leader in the crouching down state in the tent so there is one more person.

 

Hope I helped!