http://wiki.project1999.com/Sesserdr...Strategy_Guide
Level 20-40 you can do exclusively in Unrest. It does get crowded sometimes but basement is often free so if you can push through to 29/30 it becomes a lot more reliable of a camp to get.
Basically charm stuff, pet attack other stuff, use Hungry Earth (undead only root) to root whatever your pet is fighting. Use Circlet of Shadows to break charm (highly suggest investing in one of these ASAP) and either undead nuke, lifetap, or hungry earth to kill off your pet at low HP.
FD if necessary. Always keep Harmshield up. Use Screaming Terror to Mez your pet on a break.
Beyond that it's rather simple.