0 Partial Resistance
20 Elemental Amplification
20 Ice Strike
20 Thunder Spear
20 Elemental Composition
10 Teleport Mastery
10 Elemental Decrease
Ice strike will become your main training skill once you advance to 3rd. It's stronger than Cold Beam and has more range than Thunder Bolt. After you max I.S. get 3 points in amp so you can get booster. After getting booster to a reasonable level (one where the timer lasts a tolerable amount of time), you can go ahead and experiment, you can go and max Amplification for more power, max Thunder spear because it's awesome (it is! ask the other I/L's around here (except for thorr, he doesn't like T.S.)), you can put a little bit in everything and play around (tele mastery is very fun, and useful). Seal is amazingly useful too, if you want enemies to not use their special attacks. It's up to you which order you want to put points in as you'll still be training with Ice Strike, however you can get thunderspear semi-early and go hunt some bosses.
Partial resistance is rather useless, seeing you're probably not training on ice or lightning type monsters, so use your last points on Slow in 2nd job.
Now we've got freeze, stun, and slow. I/L's can easily debilitate enemies at this point. When you get Chain Lightning in 4th job your debilitating attacks will aid you in killing.
If you think PR is useful, you can go ahead and drop Composition, it's pretty redundant seeing you have Ice Strike and Thunder Spear to use already.