argh wrote a long post and it deleted itself
would suggest wearing skinny jeans the most with DMS or ankle boots. I like American apparel easy jeans in black (you'd need a small or XS) and topshop Leigh jeans (you'dbe a 25/26). I also like J brands and Paige which can sometimes be found cheaper
I like long cardis with things. Recently I wore opaques, a knit dress, a long cashmere grey cardigan from gap last year over the top and a scarf. It was so warm and toasty. I wear same cardigan with jeans too.
You could also wear leggings or stretchy black trousers, with oversized tops and DMs - eg today I wore an XL chunky knit sweater over a stripey vest top, thick black leggings, black ankle boots and a scarf - very warm
for jackets I like banana republic trench coats, or wool coats in a duffle coat or pea coat, or open coats - I found a nice one the other day in zara
I also like rain macs and parkas on some people - uniqlo had some nice ones last year without the furry bit
I like blazers but I wear unstructured ones now, or oversized. I wear them with anything. If you want a blazer that fits, go for one with a dress, but dress the dress down with boots and tights for instance, or go for one in a casual fabric, eg jersey
don't look smart, think chunky knits, autumn preppy, a bit all saints, a bit older and wiser chic lady from paris, understated