I agree that to read with this deck, throw out all your tarot learnings and just go with the deck. I think the problem people have with it is that they try to shove it into a narrow little "box" called tarot when it's actually not tarot. It's divinitory, but doesn't have much relation to tarot at all, to my way of thinking.
She has a dark sister called Olukun who lives deeper below her in the seas, and Olukun, even though I don't take her to be really maelevolent, isn't as nurturing as Yemaya. Olukun is more masculine in her attributes and if given someone we can identify with, we might think of Joan of Arc, who certainly took on a more masculine role in going to a crusade. A balanced person contains attributes of both Shemaya and Olukun, but some get an imbalance.
My research says she's a West African creation goddess who rules over the seas and lakes. Her name means "Mother Whose Children are Fish" to reflect that her children are too numerous to count. She dresses in seven skirts of blue and white to represent the 7 seas. She's like the sea---deep and unknowable, but caring and nurturing. She embodies all the characteristics of motherhood. Canonized, she's the Virgin Mary.
It's said that the sea was where we originated, so all people would then be her children.
*embla*, please correct me if any of the notes I've made are wrong, or if any of my sources were inaccurate.
Ochun is her daughter.
Yemaya's symbols and characteristics:
Love for children.
Strong temper but slow to erupt.
Sincere caring for others
Ability to see other's perspectives
Very domestic
Very protective of offspring
Attraction for lakes and oceans
Able to forgive easily
Calm attitude
Money comes easily, without worry
Emotional well-being is most important
Very caring and comforting
Quiet sense of sensuality (think of hips rocking gently like the waves lapping on shore)
Symbols
color blue
necklace of blue and clear beads
peacocks and ducks
half moon and star
rocks and shells from the sea carry her energy
She likes jewelry, perfume and flowers as offerings.
The picture on the card shows her giving birth to everything in the sea, and the salty sea is like the embryonic fluid that is gushing from her. That's what it looks like to me.