Target pets you plan to actively level. The flat XP/s from Dreadbound accelerates early- and mid-level grinds disproportionately well.
Roll until you land higher XP values (closer to 30). Since the value is fixed on application, duplicates are worth considering if you want a better roll.
Chain haunts by staging multiple level 50 candidates. Rotate through them to avoid downtime between Headless Horseman cycles.
Pairs nicely with percentage-based XP boosters from other sources to compound leveling speed.