You try your hand at growing microgreens. If you grow slow growing herbs like rosemary, thyme, and lavender you can start those now too. It is not too early to start onion seeds either.

Beyond getting seed starting mix, having pots and cells to start the seeds in, having your garden layout planned, laying in any soil treatments like fertilizers and such, and having a lighting setup, there isn't anything to do but wait for the proper time to sow seeds.

If you plan to start onions or leeks then you are already late in most areas of the country. The next thing on my list of things to start are Brassicas in late February.

Sorry I can't think of much you can do gardening wise with snow on the ground. Maybe clean and sharpen your gardening tools, Clean up the tiller and change the oil, sharpen the mower blades, turn the compost piles (if not frozen solid).

You can winter sow some flowers and herbs.

Rodney