December 21st is special. Because the world is going to end? No. Because there will be a collective awakening? That would be nice, but probably not. Other astrologers have done an excellent job of exploring the possibilities of this day. If you're interested, check out Planetwaves.net and darkstarastrology.com for reasons why this December 21st may or may not be more significant than usual.
Here's what you can count on: December 21st will be the Winter Solstice. The longest night. The Sun will enter Capricorn at 6:11 AM EST, signalling the moment when we can look forward to longer days. It will be a time of rebirth, and planning for the future. Because there is going to be a future.
Saturn ruled Capricorn is the sign of structure. Probably the last sign you would associate with rebirth. But this tells us something about Capricorn nature; this Cardinal sign steadily climbs. When things get grim, Capricorn gets determined. It cuts away (with Saturnian calculation) what holds it back while simultaneously reaching for the light. Its adherence to structure is part of its foundation; inner strength and iron will.
So if you want to focus on something this December 21st, focus on your future plans. Use the energy to let go of last year's "stuff" (you could turn it into a physical statement by burning symbols of what you're dispensing with) and then celebrate. Welcome the light of longer days into your life, and make the energy hospitable for a positive future.
Keep this in mind: the Sun in Capricorn will be squaring unpredictable Uranus (at 4 degrees Aries) between December 21st and December 25th. So the house in your chart with Capricorn in it may experience some turbulence. Last minute changes, unexpected encounters, broken rules. Perhaps you'll be forced to let go of something before you're ready. But it's all good...this is the time of year to move forward anyway, right? Think of the Uranus square as your Solstice Accelerant.
If you have planets between 0-4 degrees Capricorn or Aries, you'll be hit by this most intensely.