A trick many necromancers seem to miss completely: everyone has a skeleton. You can animate them. It is very difficult to oppose anyone when your skeleton isn't cooperating with you.

Though it isn't for the faint of heart (think about what happens when someone's muscles and tendons want bones to go one way but the skeleton uses bone magic to go a different way. Obviously bone magic wins), and I would not suggest casting this in front of a druid, paladin, barbarian, ranger, or cleric. It's also risky in front of a lot of warriors, rogues, monks, and even sorcerers and wizards. And while it has never made a bard turn on me, every single one of them has disappeared by the next morning.

It's more fun adventuring with a group of fleshies but awkward situations like that are why I generally just make my own party when I feel like adventuring or taking control of a region.