Look up some of LordFluffy’s guides.
He had links to them in this Necromancer forum.
Generally speaking, Legacy of Dreams (LoD) and Inarius builds are king for Necro’s currently. The current flavours of the month are the Grim Scythe build and the Corpse Explosion build isn’t too bad either of you don’t mind the LotD playstyle.
Just to clarify, you can use either LoD, or Inarius for both builds. The set is going to be easier to get started seeing you already have it.
If you’re not familiar with LoD, it does the same thing as the old Legacy of Nightmares (LoN) ring set, but it’s a Legendary Gem instead which is generally considered better.
I personally prefer Grim Scythe, but that’s mainly because I’m not a fan of builds revolving around LotD’s cooldown.
Here’s a couple links to the most popular Necro builds this patch.