Control the field by having Eldlich and Doomking Balerdroch join forces. You can also take control of the opponents monsters and expand your zombie army.
Some neat techs:
Use Lava Golem to get rid of problem monsters, even if Zombie World up, this doesn't count as a Tribute Summon, you can use this as a back up plan if Rivalry of the Warlords isn't up. Eldlich's 2nd effect will allow you to easily beat over it, with either itself or Balerdroch. Also if you have Zombie Necronize in hand, take control of Lava Golem, get your opponent to 1000 or less life points & let the burn damage finish them off next turn.
Use Vampire Sucker to get extra draws, either summon a non link monster from your opponent's graveyard, or summon a monster from your graveyard. You can also get free draws everytime Balerdroch revives itself which will also allow you to activate it's effect and banish one of your opponent's monsters.
If you manage to send a strong monster to your opponent's grave, use Red-eyes Zombie Necro Dragon's effect or Vampire Fraulein to steal them. If you manage to summon Shark Fortress, and you have the lifepoints to spare, used it's effect on Fraulein to let it attack twice and steal 2 monsters.
As long as you're not interrupted, Yuki-Onna the Absolute Zero Mayakashi can be easily summoned by using Uni-Zombie or Ash Blossom & another monster to summon Crystron Halqifibrax, use it's effect to summon Glow-up Bloom, then use both to summon Shiranui Skillsaga Supremecy. Afterwords use Glow-up Bloom's effect to summon a high leveled Zombie with Zombie World on the field. Then use both to summon Yuki-Onna. Don't attempt to do this on turn 1 just to be safe, a single Ash will ruin the combo.
Use Psy-framelord Omega to recycle banished cards including Mezuki, Necroworld Banshee, the Eldlixer & Golden Land S/T, Zombie Necronize. You can also use it to recover Eldlich & Balerdroch incase your opponent banishes them.