Ice Lightning Mages are relatively simple because you'll just have to focus on 2-3 skills and the rest is relatively useless. Here's what I did and will do for my I/L Mage 2nd Job: 30 ~ 1 Teleport 31-41 ~ 30 Lightning (Max) 42-49 ~ 19 Teleport (Max) and 2 MP Eater 50-56 ~ 18 MP Eater (Max) 57-70 ~ Anything (Meditation doesn't matter because Wizard Elixirs do the exact same thing) 3rd Job: 70-80 ~ 30 Ice Strike (Max) 81-84 ~ 11 Spell Booster and 1 Elemental Amplification 85-95~ 29 Elemental Amplification (Max) and 1 Spell Booster 96-99 ~ 8 Spell Booster (Max) and anything else 100-120 ~ Anything (I never used any other skill other than Ice Strike and Spell Booster) 4th Job: 120-127 ~ 20 Blizzard and 1 Maple Warrior 128-131 ~ 9 Maple Warrior 132-200 ~ Anything (I don't plan on using anything other than Maple Warrior and Blizzard for my entire Arch Mage career)
Since this question has been asked a few times, I'll go ahead and make this an official guide with picture and everything. Ice Lightning Mages are pretty popular so why not. I'm going to keep my previous post brief and elaborate on the guide.