I find the game quite easy overall, but I haven't played in some time, so I don't know if the last updates changed things (magical items, changes to the spawns etc from what I've read).
I like to play as a "nice" slavemaster. It makes the game harder at the same time.
That means no killing, raping or beatings, and only I can touch my girls, with their consent (well, as slaves, but you see what I mean); I don't send them to the brothel or be used as guinea pigs, etc. No attacking the peasants or travellers in the wild either.
For extra difficulty, no farm. Money will be tighter.
I'm not a fan of tatoos, so I don't use them. It also makes the game a bit harder since you can't get the bonuses they give.
A "no buying any slaves from guilds" condition is also interesting. It makes the early game harder, afterwards it's not really a problem anymore.