Summon Necro Advice

So I've decided to give necro a try, and summoner has always seemed fun to me, but I'm having trouble figuring it out.

For skills I maxed Summon Mastery, Skeleton Mastery, Skeletal Lich, and Raise Skeleton, with 1 point in all the Golems, Revive, and Summon Archers. I also put 1 point into Teeth and Corpse Explosion, and 1 into Amp Damage. I'm not sure if these are right, but they seem fine as I'm able to handle cows so far pretty easily.

My big issue comes with not really knowing what to aim for gear wise. From what I gathered reading through the forums -% to enemy physical resist affects my summons, so do I want to stack Phys gear like Arkaine's Wrath, Relic of The Ancients, and Titans Grip?

And as far as killing things, for cows I've been letting my army kill a few things, and spamming Corpse Explosion to much success. Will that work as well in higher levels? Am I supposed to use Skeletal Burst more frequently? Because it doesn't do a ton of damage, granted my weapon, and overall gear for right now, is pretty weak.