Not sure I have any advice …
For myself I’ve always liked clothes that lend presence, and that hasn’t changed. I’m inclined to a high low approach - mostly buying the best I can afford or access, often via sales / pre-owned, and mixing with more ephemeral cheap things. (One of my most successful outfits was a Gembalies jacket from Vestiaire, Cos vest, and Primark joggers bought in a hurry away from home, worn with some handmade white clumpy sandals.)
I’m happy in trousers or a perfect dress but find skirts most exciting and am always on the lookout for designers that hit the mark. Currently love Margiela, Sofie D’Hoore, Zara, Margaret Howell. Since I ceased to require expensive black or grey suits for work I’ve become a bit obsessed with knitwear, so have too many colourful jumpers and not enough lightweight coats or jackets.
I’ve struggled a bit with the increasing casual-isation of dressing; I love wearing old rags at home but ‘smart casual’ is really not my natural position - so I do have to make a conscious effort to avoid dressing too formally in everyday life.
The thing that’s changed since I became 60 is that I’m much more conscious of building up a store of really beautiful clothes - against a day when I may have less ability to choose what I wear. Because MN has shown me exactly what people think is appropriate clothing for old people - and it’s extremely nasty.