From 'The Encyclopedia of World Mythology', ed. by Arthur Cotterell:

Described as the 'principal goddess of the Vanir', or a set of fertility deities. She was also the goddess of erotic and sensual love, and was said to be an expert in the ways of magic and receiving the dead. Was also known for sleeping around.

I don't know much about practices I'm afraid-I'll have to look that up. But there's a bit of information if you didn't know it already.