I'm 36, size 8 - 10, flat-chested.
My current style role model is Capuchine Safyurtlu. Ditch the high heels, obv (if you're me, anyway), and switch for Stan Smiths or sandals.
About 20% of the time I (try to ) channel Kate Lanphear (aged 40) instead. Black ripped jeans etc.
Taking my lead from Capuchine, I look way more together since I ditched everything from my wardrobe that was not black, white, grey or denim. It's not boring at all (as I had feared) - I look really well put together in practically anything. She has also shown me not to fear the white jean!! Or t-shirts.
Chambray goes with everything, especially white or grey denim.
My Topshop leather biker jacket is a staple. I wear it constantly (cheaper and finer leather than the ubiquitous Whistles one).
I have 1 smart pique pin-dot Whistles suit that I wear as separates to dress things up.
Stan Smiths have been a great addition to my wardrobe. They're a huge blogger cliche, but they're also incredibly comfy and they don't seem to get dirty. I wear black Ash trainers in winter or black Ash biker boots. Or my beloved leopard ponyskin slippers.
Fave brands = Topshop (for jeans), Asos for t-shirts, but plan to stock up in JCrew in the US this summer, Whistles when I can afford it. Jack Wills for jeans and chambray shirts.