I've spent quite a bit of time looking at my own chart for significators of writing talent. I had a 31-year career as a professional technical and legal writer, producing detailed technical instructions/procedures for engineers and legal correspondence for communication with federal (US) regulators. Not terribly creative or great fun, but still quite fulfilling for someone who loves language. As a teen I tried to write and sell science fiction but never got anywhere with it. I also took some creative writing courses in college but eventually got a degree in management.
My main career driver was Mars in the 10th in Virgo, conjunct the MC and ruling the Scorpio Ascendant and the Aries 5th House. Mars makes no major aspects to any of the other planets, just a trine to the MNN in Taurus in the 6th House. Saturn and Pluto are widely conjunct in Leo in the 9th House, with Saturn trine Jupiter in Sagittarius in the 1st (actually within 3 degrees of the 2nd House cusp and ruling it). Mars makes a partile, applying, waxing semi-sextile to the Saturn-Pluto midpoint and, as the fastest of the three, brings the Saturn-Pluto influence "forward" into the 10th House. Mercury and Venus are both retrograde in Cancer in the 8th and conjunct the Sun; both are making a close waning quintile to Mars, Mercury separating and Venus applying. (These quintiles and the semi-sextile are the only planetary aspects Mars makes.) In its more positive manifestation, the quintile series suggests creative talent and has been linked to successful writers. Venus rules the 6th (and 11th) and Mercury the 10th (and 8th), and both are in quintile aspect to the elevated ruler of the 1st and 5th; both are semi-square Saturn, traditional ruler of Aquarius on the 3rd House cusp, within a few minutes of arc. The Moon is in Capricorn in the 2nd; it is making a waxing, separating (by 16 minutes of arc) sesqui-quadrate aspect to Saturn. Moon is also trine the Virgo MC and opposed the 8th House stellium. Moon disposits the Sun, the Sun disposits Saturn and Saturn disposits the Moon, making what Kevin Burk calls "dispositorship by committee" since there is no final dispositor. They do seem to function as a committee.
I've pretty much decided that Mars symbolized the career drive and creative outlet while the quintiles from Mercury and Venus signified the writing emphasis, with Saturn and Pluto showing steadiness and depth in the mental faculties while also underpinning my 17-year stretch in middle management. (Although I don't credit it for much, the Sun in Cancer is also biquintile the Scorpio Ascendant.) Jupiter ruling the 2nd and trine Saturn, with the Moon in Capricorn in the 2nd, implied a measure of success in practical terms, although with some occasional fluctuation. While relations with my various bosses were up and down over the years, I never had a position where my writing ability wasn't the linchpin of my ongoing career development.
If you don't have any obvious major indicators of creative talent in your chart, you might see if you have any tight quintiles (or perhaps biquintiles) to the planets either ruling the creativity-and-career oriented houses or dispositing the rulers of those houses, or that are otherwise sensitively placed in the chart.