Your strategy for playing as Necropolis.

Dear friend, you really should install patch 1.5 for the original game and 2.1 for the expansion – they significantly reduced the power of necromancy, and it becomes quite difficult to build an army in the first few weeks...
The best thing you can do is to upgrade Spiritual Link as soon as possible and use Resurrection until the enemy is almost dead... This allows you to make good progress against moderately strong enemies... The main thing is to build Ghosts and Vampires as quickly as possible – Ghosts for their incorporeality, and Vampires for their vampirism – 5-15 Vampires are already a force to be reckoned with!
Increase attack and, if possible, defense – choose special necromantic skills – Cold Steel, Haste, and Grave Chill – and your undead troops will start performing miracles :)