I think from looking at others it seems to be:
Hair no longer than shoulders, ideally an all over type of shade or with babylights (this is definitely not me right now)
Nude/red/burgundy/plum shellac nails
Plain tailored clothes in natural fabrics. Chinos, shirts, ballet pumps, boots, minimal jewellery (studs and a ring and a watch or studs and a necklace and bracelet) dresses which tie at the waist, neutral or nautical colours, camel coat, mac in navy or camel, two bags of high quality which are in black, navy, camel or grey. Less is more, minimal make up, get your eyebrows dyed and threaded and your lashes permed and dyed. A facial once every 6 weeks, haircut needs to be regular as well. A cashmere cardigan is a must. If you do have a print make it on your cardigan and the rest of your clothes quite plain.
Love the comment about gold and silver zips, buckles matching. I feel like that's me 😂
Designer inspiration is hobbs, joules, maxmara, whistles, triology, sandro, weekend at John Lewis. You can find things you like and then Google cheaper alternatives and get these at next, h&m, warehouse etc. However, I would invest money in good shoes and coats.
Years ago when I was a young girl I read a good book called A Guide to Elegance: For Every Woman Who Wants to Be Well and Properly Dressed on All Occasions by Geneviève Antoine-Dariaux
I don't follow all of the above but I try. You end up having a capsule wardrobe you wear more than if you bought lots of stuff regularly, so can help with expenditure in the long run :)