I was planning on rolling a destruction/conjuration mage (points in alteration too for survivability) but I distinctly remember how frustrating the early game can be for a straight up mage, so any tips on surviving the early game?
"If he pulls a dragon out of his ass I'm leaving!" - Varric, Dragon Age II, Legacy
Early game is where the Mage thrives, because the spells in vanilla don't scale well at all since higher level NPC's get surplus amounts of health, magicka, and stamina.
When it comes to actual tactics, note how projectiles from spells will be fired on an angle if you strafe, kiting doesn't hurt, and shields are actually pretty good on a Mage - not only you can block more effectively and utilize Block perks, but it doesn't negate Mage Armor either.
My character is a necromancer who uses destruction when necessary so raise zombie and conjure spells are vital. You can purchase a raise zombie spell right when you reach the first town. You won't have access to many minions at first so you will still have to do some fighting. I use a sword in one hand and a fire spell in the other. I pepper them with fire periodically then slash them after since fire increases the damage they take.
I have a bunch of mods that improve the mage/necromancer experience though. A vanilla mage is not only a chore but rather boring, IMO.
I use Psikotik Necromancer mod, Apocalypse Spell Package, Better Magic, and Magic Duel.
Get the Lord Stone and "Agent of Mara" early on. That's 40% magic resist with little effort. A Breton would be at 65% if you're willing to re-roll. Makes a big difference against mages and dragon's breath. The cap is 85% and can be easily reached with items and, optionally, the perks in Alteration.
Lord Stone also adds 50 armor rating. Alteration's first Mage Armor perk is relatively easy to get to. Alteration 30 I think. That doubles the effectiveness of your armor spells, so added to the Lord Stone you should be at 180 armor with just the apprentice Stone Flesh spell pretty early in the game. That's not going to let you laugh off a bandit's sword, but it may give you room to breathe. You'll still want to kite melee enemies or find a way to disable them. If you're not going to use a shield, get a follower to tank for you.
Also, don't forget that Bound Weapons can be poisoned. Even if you're not terribly skilled with the weapon, it can be used to deliver useful poisons like Lingering Damage + Paralysis to enemies that get too close. Or at a distance to deliver poisons with a Bound Bow. You can start a fight with a poison delivered by Bound Bow that makes them weaker to your chosen offensive spell as well. Illusion's Silent Casting perk is handy for not being detected while you're prepping your spells for a fight.
1 - buy the flame atronach tome from Farengar 2 - hide behind cover and spam flame atronachs (when one dies, recast immediately) 3 - when there's one AI left, but no archers, go to town with your destruction magic
The AI usually focuses on your atronachs, so you could generally hold them in place indefinitely with a good magic regen outfit and Mage hood.