The build starts out a little rough, especially if you're playing without a companion. Using a bow as your primary weapon requires a lot of running away, spinning around, and popping a shot or two. Plus, the things you can conjure at this point aren't the best tanks; undead via Raise Zombie and Reanimate Corpse can generally become overwhelmed and killed easily, as can be a conjured Familiar. Conjured Flame Atronachs generally attack from range, instead of getting into the fight.
The real key to this build is getting your conjuration up to level 50, which I accomplished by level 14. At this point, you gain access to three very valuable spells: Bound Bow, Conjure Frost Atronach, and Revenant. With the Mystic Binding perk, as well as perks in the Archery tree, the Bound Bow easily trumps any other bow available at this level (my damage rating went from 33 to 90). Frost Atronachs make great tanks, and can easily take a beating while you pop shots. And of course, for us Necromancers, Revenant lets us raise more powerful undead once we've made a few corpses. Protip: if you come across a dead werewolf in your travels, they make excellent tanks. Their knockdown attack makes your opponents highly vulnerable to a few cheap shots from your bow.
I chose Heavy Armor as my third skill, since it makes you less squishy when the fight gets up close and personal. I've yet to perk into the skill, as my focus has been Archery and Conjuration. Also, I currently wear a mixed set of armor, as I found some archery gear in my travels (a circlet and some leather gauntlets). Once you level Conjuration to 50, you could easily switch to casting gear (robes instead of armor), as the fight rarely gets in-your-face at this point.
