There’s a ton of ways to interact with any god or goddess. Trance, divination, learning to listen for their voice, ect.
As for offerings…as with all the Norse gods, she is fond of mead. She’s fond of honey as well, and in my experience honeycomb is accepted with great delight if you can get it.
Warm fresh bread, and fresh fruit.
She’s fond of coffee as well, and tea. Either of these sweetened with honey is very good. She likes perfume, and fresh flowers, and cosmetics. In the case of cosmetics and perfume, she likes it even more if you wear them and enjoy them.
Jewelry. Beautiful jewelry delights her. And same as cosmetics and perfume, it delights her to see her followers wear it in her honor.
Boldness pleases her as well, from her followers. I dedicate my time spent training in martial arts to her; she is a war goddess, remember, and such things please her.
Sex, if you enjoy sex. Dedicating sexual pleasure to her pleases her very much.
Learning more about magic. She taught Odin the art of sedir, remember, and Odin holds her abilities and advice in high regard.