A shelf, a windowsill, or the top of a chest is enough. Cover it with clean cloth. Place one image or symbol, one light, one vessel for water or drink, and one dish for solid offerings. Face it east if you can. Nine niches do not require nine altars — one surface, rotated by season or by need, is the older practice.
Wash your hands. Light the flame. Speak the goddess's name three times before you speak your request. Read her prayer aloud rather than in thought; the voice is the offering. Sit for the length of nine slow breaths afterward, asking nothing.
Pour water, milk, wine, or mead into a bowl and later onto living earth or the root of a plant. Never down a drain if a plant is within reach. Pour with the right hand, in three motions, keeping the last portion for yourself only where the tradition permits shared food.
Flowers stay until they turn, then go to compost or earth, not the bin. Food left overnight is returned to the ground or to birds. Burnt remains are gathered and buried. Metal, cloth, and beads may remain permanently as votive gifts and should not be reclaimed for ordinary use.
Do not petition any of these goddesses to compel, bind, or humiliate another person. Do not mix incompatible offerings from different pantheons on one dish. Do not bargain with what you cannot deliver. Do not let the altar gather dust; neglect speaks louder than any prayer.
These are living traditions with living communities. Where a rite belongs to a culture not your own, learn its terms before borrowing them, prefer the simplest honest offering, and let the sources of a practice be named rather than smoothed away.