“The Veelas’ themes are fairies, nature, healing, wealth and abundance. Their symbols are sweet bread, sacred fairy plants (oak, ash, thorn, foxglove, etc) and healing herbs. These Balkan Goddesses preside over the woodlands and have the power to heal or harm, depending on the circumstances. The Veelas kindly treat humans who respect them and the earth, rewarding them with the knowledge of how to work harmoniously with the land, which, in turn, creates prosperity and abundance.
In ancient Macedonia, today was a time to appease the spirits of nature, called Drymiais. We can follow their customs by not harvesting any plants (especially vining ones), and not doing any cleaning (especially with water). If you must do one of these forbidden activities, carry iron to protect you from mischievous fairy folk.
If you live near any oak, ash or thorn trees, leave under it a little gift of sweet bread for the Veelas. As you do, whisper a short request to the Veelas for renewed health and permission to gather some herbs associated with health and healing today. Afterward, look for an ash or oak leaf or some tansy flowers. These will act as an amulet for well-being whenever you carry them with you.
For prosperity and abundance, and to improve your connection with the earth, give the Veelas an offering of honey instead, and eat a bit yourself to consume the earth’s sweetness.”
(Patricia Telesco, “365 Goddess: a daily guide to the magic and inspiration of the goddess”.)
Medussa, in an piece written for the Order of the White Moon, presents a very clear picture of who these nature spirits were: “The Veelas, also known as the Vily; the Eastern European name for ‘the Goddess of energy moving through the earth as nature’. They were an ancient Kith long before the Sidhe rose to dominance over western Kithain. They live mostly in Eastern mountains and forests. They were born from the primordial worship of the Great Mother in Her warrior aspect.
The Veelas are the most beautiful women but not human; they are tall and strong, with moon bright skin and white golden hair that fans out behind them, even when there is no wind. They have flashing eyes of grey or pale blue, their voices are low and musical. But do not be mistaken, they are warrior huntresses and very protective of their terrain. They are great shape-shifters able to change into animals such as snakes, swans, falcons and horses. They love to play and dance and if contacted with a great respect they may grant you health, wealth and abundant crops. But if an intruder should show disrespect they would dance the offender to death.
The Veelas prowled the land from Scythia in the south to the Capland in the north sharing dominion with their cousins the Valkyries. They enjoy their most satisfying relationships with trolls. The Veelas are extremely given over to honor and battle.” 
This led me to dig a little deeper and found reference an actual Goddess named Vila. ”Vila (pronounced vee’lah) is the eastern European name for the Goddess of Energy moving through the earth as nature. Vily (plural) are known as female spirits that lived in the woods, mountains, and clouds; they could shape shift into swans, horses, falcons, or wolves.
In Slovakia, they are regarded as the souls of dead girls that lead young men to their deaths; they fire arrows that may disturb one’s reason.” 
Patricia Monaghan writes that Vila was “one of the most powerful European Goddesses [also] called Samovila…or Judy according to the language of the people, who pictured this woodland forces as a fair-skinned winged woman with glistening garments and golden hair falling to Her feet. She lived deep in the woods, where She guarded animals and plants as well as cleaning rubble out of streams and assuring sufficient rainfall.
Hunters were wary of beautiful, well-dressed women speaking the languages of animals, for Vila was fiercely possessive of Her wild herds. Should one be injured or – worse yet – killed, Vila mutilated the offender or lured him into a magic circle and danced him to death. Alternatively, Vila might bury him in rocks by starting an avalanche, or simply cause him to keel over with a heart attack.
Vila was able to masquerade as a snake, swan, falcon, horse or whirlwind. Cloud Vilas could transform themselves into clouds or fog. Born on a day of soft misty rain, when the sun formed miniature rainbows on the trees, She knew all the secrets of healing and herb craft. Should a human wish to learn Her skills, blood-sisterhood was forged with Vila. The applicant appeared in the woods before sunrise on a Sunday of the full moon. Drawing a circle with a birch twig or a broom, she placed several horsehairs, a hoof, and some manure inside the circle, then stood with her right foot on the hoof calling to the Vila. Should the spirit appear and be greeted as a sister, Vila would grant any wish” (p. 311).
Goddessrealm.com, “Vila Goddess of Transformation“.
Medussa. Order of the White Moon, “The Veelas“.
Monaghan, Patricia. The New Book of Goddesses and Heroines, “Vila”.
Finnegan, Margaret. Margaretfinnegan.blogspot.com, “Goddess of the Week: The Vily“.
MXTODIS123. An Inner Journey: The Moon, Mythology and You, “Samovila“.
Mydailygoddess.blogspot.com, “Vila: Shape-Shifting“.
Omda.bg, ”SAMODIVA” (translated from Bulgarian).
Stanton, Sandra M. The Goddess in World Mythology, “Samovila“.