ancient, primitive
traditional
daily, nightly
Sunday, etc.
family
Eating around the table was a family ritual that could not be broken.

tribal
little
A cognac before bed is one of our little nightly rituals.

elaborate, solemn
bizarre, strange
empty
Bargaining at the markets is now just an empty ritual.

secret
secret rituals in the sacred forest

magical, religious
public, social
sacred
Catholic, Hindu, Jewish, etc.
pagan, satanic, shamanic, voodoo
burial, cleansing, courtship, fertility, funerary, healing, initiation, mating, mourning, purification
hazing (AmE)

conduct, do, enact, go through, hold, perform
She had to go through the ritual of kissing the toys before her son would go to sleep.
rituals performed by druids on Midsummer's Day

undergo
Boys undergo a circumcision ritual to usher them into adulthood.

follow, observe, practise/practice
Their funerals follow the rituals of the Catholic church.
They practise/practice certain rituals in connection with rites of passage.

complete
It takes several days to complete the ritual.

begin
Jake began the evening ritual of asking about everyone's day.

make
He makes an elaborate ritual of washing the car.

become
Her visits to her aged father have become a ritual.

take place

in a/the ritual
Women's roles in the rituals of many religions have been limited.

Ritual is used with these nouns:
chant, dance, denunciation, magic, murder, prayer, sacrifice, slaughter, suicide, vessel