I think this is a really good question. The best advice (and one that I followed) was to be really brutally honest with yourself, declutter the stuff that you didn't wear (or made you look less than great) and look at what you actually do wear. I did the following:
Pulled all my clothes out (not the ones out of season, though, just current season) and picked out the ones I liked most/wore the most/felt the best in. Then I looked at the general theme of those and what they told me. For me, the outfits I best liked were trousers and jeans, few dresses but no skirts. Lots of neutral, some print but nothing ditsy/dainty/overly feminine. I gravitated towards oversized, slightly boxy, but also certain necklines and dress lengths etc. I made a list of things that suited me (v-necks, highnecks, over the knee, high-waisted etc) and what I liked (stripes, neutrals, bright red, bright green) and what I didn't (skinny fit trousers, crewnecks, florals, maxi dresses, pastels)
I then decluttered heavily. I got rid of things I didn't feel good in, and what went against my likes. There was a lot, and I didn't miss any of it. I also did declutter stuff I wore, but which realistically made me look not so great (like skin-tight vest tops - a slightly looser fit is much more flattering to me)
I then made a pinterest board of people who dressed the way I liked, or clothes I saw online which I felt drawn to, and found parallels in those. I added a few things on my shopping wish list. I was really critical with what I bought.
So my wardrobe looks quite different at the start of 2023 than it did in 2022. I've kind of defined my style as classic/edgy/minimal. For example, I have a cream lace top but I would only ever pair it with black leather, which makes it quite edgy. Paired with a floral skirt for example it would be way too cutesy.
I think finding your style takes a bit of trial and error, but a good way to start is to really think what you currently have that makes you feel good and comfortable and go from there. I follow a few youtubers and instagrammers who reflect my style and I get lots of tips from them.