Mystic i believe her name is spelled Yemaya if you mean the African Goddess of the Sea(Orisha ) .She also is incorporated in Santeria path .People set up altars for her ,they also sell statues with her image ,but you can substitute it with picture or oracle card dedicated to her .Some Goddess Oracle decks have her included .
You can put on her altar sea water ,blue stones (aquamarine ),blue and white candles ,sea shells ,flowers on (especially white and blue) ,because she is depicted in such colors .I have heard that her number is seven so you can give her gifts in seven like seven coins .You also can wear pearls and white and blue cloths to attune more to her .People write and say prayers to her .
Here is example for one such type of prayer
For contacting deities you simply must dedicate a place for them in your life and get yourself attuned and open toward them ,many people set altars for them and spend some time studying ,calling ,praying upon them .Sometimes deity will call you and sometimes you feel drawn to it .It is similar to building relation with human friends it takes time and devotion .
I do not work directly with deities i rather study them ,but that is how i have heard and read things are for others .