MM. Imbolc is such a lovely Sabbat (but aren't they all?). Here's what my coven does to celebrate Imbolc:
1. We hold a circle in honor of Brighid, Who is strongly associated with Imbolc. The God Whom we honor varies, but in the past we've paired Her with Herne or with Bel. She's a Goddess of smithcraft, poetry, inspiration, and transmutation, among other things. She is also associated with healing teas and is said to have gifted the Celts with writing.
2. Imbolc is strongly associated with cleaning and repurposing. Now is a great time to clean all your ritual tools, clean the house, and to do stuff like making rag rugs or recombining candle wax for re-use.
3. Imbolc is associated with the first lambing of the year, so that means that goat milk is plentiful. We cook with milk and cheese at this time to honor the spirit of the Sabbat. I make a lovely baked brie for this Sabbat.
4. It is customary to briefly light all the lights in the house on Imbolc night to welcome light back into our lives. Often my coven will vigil all night at the covenstead on Imbolc and then drop the circle in the morning. During vigil we might clean our ritual tools, recombine candles, do divinations, etc. At dawn the youngest member of our coven wakes everyone who fell asleep with a song and we have a sunrise breakfast together before closing the circle.
5. If you wish, you can make "Brighid's crosses" out of corn husks or other natural material. You can find tutorials on Youtube.