Tips for Pure Electromancy Build
For pure electromancy, going for the left side of Magic Mastery works best.
Seal of Finesse for extra Cooldown Reduction, Seal of Insight for even more damage and energy regen, and up to Thaumaturgy passive for Miracle Chance and Miracle Potency (aka. moar spell crits!). I’m not a fan of T4 Magic Mastery, but I guess if you want to minmax, there’s another passive that adds Magic bonuses.
Putting points into Geomancy up to Petrification would also be very useful, since Rocks give extra Magic Power too and Petri can be used to stop enemies in their tracks.
Athletics – Dash and Leg Sweep are useful as safety/escape skills.
Shields – if you decide to not use a staff, Hold the Line! is an amazing damage reduction skill. There are some unique shields and one-handed weapons for casters to use this combination.
Staves – either you put just one point into Hail of Blows and bonk the random enemy that managed to get close.
You can go Hybrid and utilize the passives on the right side of Staves and Magic Mastery to boost both types of attack. Going into melee combat works well with Impulse, but not with Ball Lightning. You probably wouldn’t want to wear mage robes in that case either.
Armored Combat – has some nice passives and generic defensive skills that even a mage can utilize, but unless you decide for that hybrid, I’d recommend picking something else.
Survival – Learning the first aid side can save your life in a pinch, but from my experience, late game electromages don’t usually get in trouble. The passives are good, but they won’t affect your combat performance. Make a Halt is good for replenishing Vigor at camps.
Warfare has mostly things for non-casters, so it’s not very interesting. You might try to use War Cry to group up a large quantity of enemies.
The other weaponry trees are basically pointless to learn.