A little introduction here, Evoker is an extremely INT-sensitive caster class. A little bit of INT goes a long way here, and a lot of INT... well, lets just say damage isn't an issue.
If you start off with Earth mastery, you wanna rush to Ring of Flame and Stoneform. In normal difficulty, this makes killing ridiculously easy. As soon as you max Ring of Flame, you're gonna want to max Earth Enchantment to push that damage further. An aura-mancer works well in Normal, so you might as well go with one for the time being.
Aim for that asap, it will make things very easy for you in Normal.
After you max those two skills, (EE and Ring of Flame), start working on Dream. Just pump the mastery. By the time you are level 23, you should be able to get Trance of Wrath. Max it asap. By level 27, it should be maxed and you should now have beyond ridiculous AOE damage as you walk around. (~120 damage per second, minimum.) At this point, max out Lucid Dream and Premonition, should take about 5 levels(til level 32) and what this does is a) stretch out your electric burn damage, and b) make it much easier for you to take hits. By taking Lucid Dream, you're stretching that EBD damage from ToW to 66 damage per second, minimum, giving you a total of 142 damage per tic in your 3 meter AoE field. (ToW is 5 meters, RoF is 3.3 meters at max level.) At this point, most mobs should be laughable.
Here is a video of how easy it is even at level 32:
(note: my stats are about 2:1 INTEX, though I probably should've invested more in DEX. I have about 180 DEX and DA which makes this character very fragile, this is why I grabbed stoneform and heat shield in advance)
At this point, you've maxed out all your AoE skills, and your buffs to enhance those skills. So your skills are now dependent upon your stats and gear – which kinda prevents the amazing damage growth you were receiving before. Not to mention you're nearing the end of act 3 at this point, if not already in act 4. You have two choices now – either switch your build into the REAL evoker, or add some more spells to your auramancer's arsenal. Typhon might prove to be a little hard as a pure auramancer – and it only gets worse from there. This is why I suggest switching. A really useful skill in Act 3, is Trance of Empathy. Either switch out of Trance of Wrath or something, but ToE becomes very useful against guys like Typhon or Barmanu who can deal TONS of damage in a few seconds. With just ToE, and Stoneform, you can tank the meteor showers and reflect ridiculous amounts of damage. Anyway.
Here are some videos to show the effectiveness against bosses:
Now, this build isn't an auramancer build, so I'm not going to explain how to make one. I find that auramancers really become super gear dependant later on, and are generally very difficult to play as in legendary. I've tried, and it's either you kill tons of stuff, easily and then you get one shotted, or you just get one shotted. It's tricky, and has to be played with the right combos.
So instead – here's your basic “Freddy Kreuger” style build. Skip to section “II” to go right to after level 32.(name stolen from Violos' build, and actually uses most of the concepts discussed in his guide, so most of this is his findings)