Like others have mentioned, poisons are great, even the weaker ones with 10-15 hp dmg. As an archer I have a ready supply of various poisons, the most used being weak health dmg and poison dmg. For bosses and larger enemies I like to use lingering poisons and paralysis/slow effect poisons. Enchantments with fire is my preferred effect and always keeping an eye out for the next strongest bow and arrows.

I did alot of my levelling on wildlife and bandits as I replenished ingredients to restock my poisons for dungeon runs. Oh and yeah, leave the companions and shadowmere at home....pain. in. the. butt.