The only stats that works in acc slot ist Enhanced effect
So this slot is mostly only used for heal charms. Also keep in mind acc slot casts are weaker than the main slot, but also cost less mana
for the first run I'd recommend two abilties:
Powerstrike and Retribution
Both do high single target damage, which helps a lot with clearing evil presences with low equipment
Powerstrikes charges with you attacks and Retribution every time you take damage (please note, taking a hit with 0 is not taking damage and doesnt charge it!)