Even my warrior in smithed heavy armor can take quite a bit of damage from two or more high level archers. How do you cloth mages find it?

Use armor spells.

When I played on my mage I would usually get killed by draugr with ebony bows. I would usually just try to Fus Ro Dah them so that they were knocked down and could not fire arrows at me and I would finish them off while they were on the ground.

I use a highly advanced technique, known to we experts as 'run like crazy'

that's one of my favorite techniques.

Dual Casting, Summoning, Runes, Wards, Spamming Ice Spikes, Lightning, Fireballs. At lower levels they are a menace, but they can be easily distracted or killed.
EDIT Running away in a curved path from them is an excellent option,too.