Imbolc is on Saturday - that is the 'official day' however if you see snowdrops pushing up through the soil or even flowering already, you can have your ritual at any time now. Imbolc is not as fixed as Halloween date-wise, as it is usually celebrated with the appearance of the first snowdrops - and they will appear at different times in varying countries. SO do what feels right for you.
To me, Imbolc is a Celtic festival and as a Scot, I welcome Bride (rather than the Irish counterpart, Brigid or Brede). I use white candles and a pale green altar cloth (you could use a white altar cloth here if you wish). I light the candles and go to my front door at night, opening it and welcoming Bride in. I see a tall, dark haired young woman in white as she enters my home, and I lead her through the house, with the candle to light our way. No part of the house is neglected (and this is why I clean beforehand (this is the forerunner to spring cleaning!)). This is also a type of house blessing.
Some people will make corn bread at this time but as I celebrate this time as a Celtic festival (and corn did not grow in the UK/Ireland prior to a couple of hundred years ago), I bake soda bread - recipe on my last post. It's very easy and native. however, if you live in America or anywhere else in the world where corn was native, go for the corn bread. Again, this is entirely up to you.
Making a brigid knot or a corn dolly is something else many people do at this time, tying it off with red ribbon. There are hundreds of site on how to do this, including youtube video's. Here is one example : How to make a Brigid Cross
Remember that while they will state using straw, you can use lavender stalks and other similar material.
If the weather is not too horrific, try to go out and have a look at some greenery, spot a few snowdrops, which are the symbol of Imbolc. This is the first Goddess festival of the year and the energy is expectant, soft, that breath before the burst that is Spring.
BB
On another note, I have written 3 books. 2 are part of a series set in Scoltand about the Sidhe, fairy folk. Available on kindle and in paperback:
The Island of the Mist is book 2
The Stone in the Sword is book 1
The 3rd book is an adult, sexy witchy werewolf/vampire story set in New York and featuring a strong female lead character, again available in kindle and paperback formats:
The Wolf, the Witch and the Coffin