Tactical basics.
1. Heroes: Galtran, Izra, Vidomina. Other possible options: Tant, Vokial.
2. Vampires with a castle should be built during the first week.
3. Earth magic is essential for the Necromancer, as is basic wisdom. Logistics is also important, of course.
4. Key spells: Raise Dead, Haste, Teleport. Town Portal, Fly, and Dimension Door would also be useful. It is worth paying attention to the "Forgetfulness" spell.
5. Main advantages: hordes of free skeletons, vampire lords.