can anyone give me a good necromage build?

Head to the Ritual Stone straght from Helgen.
Head from the Ritual Stone to Ironblind Barrow and get the Steel Battleaxe of Fiery Soul Trap, use it to fill the two Black Soul Gems that are looted off of the Boss Draugr.
Kill the young Redgaurd/Breton and loot her Steel Plate Armor. A set of Heavy Armor will aid your character when your summons die in mid battle.
Once you have cleared Ironblind Barow, your character may want to take the road to Morthal, there is a Staff of Revenants inside a small tomb to the right along the road between Labrynthian and Morthal.
Use Bound Weapons to increase your Conjuration Skill, I have had to resort to spamming Soul Trap. The problem with Thrall Spells on an NPC is the Level 30 cap. I will cheat to get the Master Level spells from the College as early as possible. You may want to Train Restoration as soon as possible as well, to get the Necromage Perk.
When you can get a Thrall, head to a known Vampire Den and get Sanguine Hemophilia.
Enjoy being an Undead Necromancer, and feeding off of the living. Lydia when modded is a fine healthy specimen for feeding purposes, and can be kept in a known location.
I do not normally play this type of character because of difficulties in keeping a safe reliable blood supply, and most of my characters would kill a known Necromage on sight.
EDIT typing "necromage" in search will pull older threads with more detail than I can type and remember.