Mortals becoming Gods and Goddesses

I posted an answer to a question on Quora "How can a mortal become god/goddess in Greek mythology?" It was solely about Greek mythology but I also included non-Greek myth examples. This is what I wrote:

Yes. In real life, mortals became deified. Its similar to cannonising people into sainthood today. Okay a list of deified mortals in Greek myth includes:

Psyche

Hercules

Ariadne

Dioscuri (Helen of Troy’s twin brothers)

Luekeothea

Asklepios

Ganymedes

Palaimon
(Edited: I want to add some more deified mortal women that includea Ino, Bolina, Hilaera, Hemithea and Parthenos. )

Deified Mortals - Thei Greek Mythology

A few ways to becoming an immortal is:

Eating a mermaid, according to Japanese folklore, a young nun ate some ningyo meat and became immortal… she lived for 800 years.

Reverted elixir or haundan is used to help the body’s cells continue and keep working and working until the body never ages. Its cinnabar and Taoists regard it as an element of purifying the body. This method became lost in time when wealthy people in the Tang dynesty ate some and died. The true ways of getting this to harmlessly ingest and cause immortality has been forgotten.

Ingesting extinct plants caused immortality (or to be exact, a very polonged life). Peaches were once thought to give immortality but these fruits have become domesticated and ordinary now. Other fruits to give immortality are golden apples. These are found in a secret unknown orchard guarded by a goddess and a dragon. Ambrosia, a special honey drink or mead with an ingrediant lost in time gives immortality.

Original source at Quora here