Your strategy for playing as Necropolis.

Quickly get archers and Grand Mages up to level 3, as there's no point in building levels 4-5 at the beginning of the game. Also, build up to improved vampires, establishing a line along the gold mines. While troop costs are still relatively low, advance to the capital. In short, build in sequence: gold mines, warriors, and Grand Mages. Then, prioritize Archliches and Dragons, aiming to get them as early as possible, before Messengers. Finally, upgrade all forts. That's a brief overview.