Mercury is about to leave fire sign Sagittarius and enter cardinal earth Capricorn (exact December 31st at 9:03 am EST). This can mark the initiatory time of an undertaking -- something substantial that is well-thought-out. Or it's a short (to January 19th) period when wild, original, novel ideas find their way to form. The bridge between idea and reality begins to take shape.
Transiting Mercury can be a point of reference to develop a concept -- lately the mercurial mood has been one of expansive views, truth seeking and telling, spontaneous hits -- a fusion of instinct and intuition ( Sagittarius). Along the way, Mercury hit Uranus Aries to spark all-original material and this is worth noting. Those fleeting flashes might be worth developing further, while Mercury is in Capricorn.
Natal Mercury (the one in your chart), tells a story about how you go about developing your seed ideas. This question on that comes from a post titled Mercury Aries and Outrageousness. Michelle asks, "Where in a natal chart does one look for advice on what subject to write about if one wants to be a successful writer? I have a grand trine (Mercury in Aries -1stH to Pluto in Leo-6thH to Saturn Rx in Sag-10thH). I've been told I can write, but just don't know where to start or what subject. Any thoughts you could share?"
My first impression is that your medium with words, could go off the page and into the spoken word -- as an educator, a motivator, humorist or travel writer. There's a sense there, of being a force of healing, when you share your own philosophy in a colorful way. You could begin by keeping a journal of scenes (dramas) you experience in day-to-day life, especially what happens when you have outbursts, outrages or bursts of insight. These scenes could string together in a memoir, or become fiction or a screenplay. I like characters that blurt out the truth, and your writing could "show, not tell" (as writing teachers always say), the magic and hilarity that ensues.
Taking a look at the whole chart, every planet could be a resource for spin-off ideas, of what to write. Your natal Sun is a guide to topics that you can find staying power with, since it's likely in synch with your purpose. Venus is an entry point, for what moves you, what you love about life. And Mars sets off motivation, so it's a lead to what lights your (creative) fire.
This is a natural time to think about goals, since winter solstice is the solar new year. I've just started reading Paulo Coelho's The Alchemist with this line, "Remember that wherever your heart is, there you will find your treasure." That is inclusive of your natal energies, but something that's much bigger than the sum of its parts. Good luck to you and everyone with a dream in 2013!Getty Images