Introductions should be gradual over days/weeks. Rushing can overwhelm and scare the animals.
Swap bedding between pets so they get used to each other's smell first.
Give cats high perches and dogs lower areas. Feed them in separate rooms at first.
Positively reinforce relaxed, friendly interactions between the pets during meetups.
Introduce the pets one at a time for shorter supervised sessions.
Try introductions when pets are distracted with toys, treats or meals.
Ensure cats have an escape route and safe hiding spot if frightened by dogs.