Because of the charge time, how do you do it. Flame atronachs have the obvious hand gesture, but other enemies projectiles are just so unpredictable, paricularly shock mages because of instant attacks. I'm a lv 3 high elf on legendary, using destruction/alteration/restoration

You'll tend to have to keep the ward up on the off chance an enemy mage might attack. However, I suppose you could also watch for any movement in the enemy mage's arms, since they must raise their hands to cast spells.